NO800617L - PROCEDURE FOR THE PREPARATION OF 6-BETA SUBSTITUTED PENICILLAN ACIDS. - Google Patents

Description

One of the most well-known, and a widely used group, of antibacterial agents are the so-called Æ-lactam antibiotics.

These compounds are characterized in that they have a core consisting of a 2-azetidine pn-(β-lactam) ring fused to either a thiazolidine or a dihydro-1,3-thiazine ring. When the core contains a thiazolidine ring, the compounds are usually generically referred to as penicillins, while, when the core contains a dihydrothiazine ring, the compounds are referred to as cephalosporins. Typical examples of penicillins commonly used in clinical practice are benzylpenicillin (penicillin G), phenoxymethylpenicillin (penicillin V), ampicillin and carbenicillin, and typical examples of common cephalosporins are cephalothin, cephalexin and cefazolin.

Despite the widespread use and widespread acceptance of β-lactam antibiotics as valuable chemotherapeutic agents, they nevertheless suffer from the main shortcoming that certain members are not: active against certain microorganisms. It is believed that in many cases this resistance of a particular microorganism to a given β3-lactam antibiotic arises from the microorganism producing an β-lactamase. The latter substances are enzymes that cleave the jS-lactam ring in penicillins and . cephalosporins to form products free of antibacterial activity. However, certain substances have the ability to inhibit 0-1 act arnas er, and when a £-lact arnas é^ inhibitor is used in combination with a penicillin or cephalosporin, it can increase or enhance the antibacterial effectiveness of the penicillin or cephalosporin against certain microorganisms. It is considered to be an increase in antibacterial activity when the antibacterial activity of a combination of an 0-lactamase-inhibiting substance and an Ø-lactara antibiotic is significantly greater than the sum of the antibacterial activities

to the individual components.

The present invention relates to a series of 6-Æ-substituted penicillanic acids and in vivo easily hydrolyzable esters thereof which are powerful inhibitors of microbial β-lactamases and increase the effectiveness of β-lactam antibiotics. The invention further relates to 6-/3-substituted penicillanic acid esters in which said ester part is a penicillin carboxy-protecting group, where the esters are useful chemical intermediates for the corresponding acids.

The invention also relates to a process for the preparation of the 6-O-substituted penicillanic acids, their easily in vivo hydrolyzable esters and esters thereof in which said ester part is a penicillin carboxyl protecting group.

Pharmaceutical preparations comprising the above-mentioned 6-/3-substituted penicillanic acids and hydrolyzable esters together with certain Æ-lactam antibiotics, and also a method of increasing the effectiveness of certain /3-lactam antibiotics in combination with the above-mentioned 6-/3- substituted penicillanic acids and hydrolyzable esters are also part of the present invention.

6-Substituted penicillanic acids and certain esters have been prepared over 6-diazopenicillanic acid (Heiv. Chim. Acta, 50, 1327

(1967), but the orientation of the substituent is in the α direction. 6-a-Hydroxypenicillanic acid is also prepared from 6-diazopenicillanic acid and its esters (J. Org. Chem., 3J9, 1444 (1974). 6-a-Benzyloxypen.±cillanic acid methyl ester is discussed by Manhas et al., J. Heterpcycl. Chem., 15., 601 (1978).

Certain 6,6-dihalo- and 6-halopenicillanic acids are discussed by Harris et al., J. Chem. Soc, 1772 (1977). In each case the 6-α-epimer of a mono-substituted penicillanic acid is described .

Later, Loosemore et al., J. Org. Chem., 43, 3611 (1978), stated that treatment of a 6-α-bromopenicillanic acid with base epimerized a portion of the compound to give a mixture of 6-α- and 6-β-bromopenicillanic acid comprising approx. 12% of the /3-epimer. A similar mixture was obtained by a hydrogenation of 6,6-dibromopenicillanic acid, in which the Ø-epimer comprised approx. 30% of the total amount. It was also shown by Pratt et al.,

Pro. Nati. Acad. Sei., 75, 4145 (1978) that the β-lactamase-inhibiting properties of a mixture of 6-α- and 6-β-bromopenicillanic acid were in relation to the amount of 6-β-bromopenicillanic acid in said mixture. The findings of Pratt et al. is confirmed by Knott-Hunzikér et al., Bibchem. J., 177 at 365

(1979) by showing that a mixture of 5% 6-j3-bromopenicillanic acid and 95% 6-a-bromopenicillanic acid inhibits /3-lactamase, while the a-epimer alone is essentially inactive.

U.S. patent 4,093,625 claims the production of 6-/3-mercapto-penicillanic acid and derivatives thereof as antibacterial agents.

Cartwright et al., Nature 278, 360 (1979) state that although 6α-chloropenicillanic acid is a poor inhibitor of β-lactamase, the corresponding sulfone is a moderately good inhibitor.

Roets et al., J. Chem. Soc., (Perkin I) 704 (1976) identifies benzyl-60-chloropenicillanate as a by-product of the reduction of benzyl-6-oxopenicillanate after hydrochloric acid treatment of the product.

Later, John et al., J. Chem. Soc. Chem. Comm., 345

(1979) discussed the preparation of benzyl-6/3-bromopenicillanate from benzyl-6,6-dibromopenicillanate using a stannous hydride reduction.

The 6-O-substituted penicillanic acids according to this invention have the formula

or a pharmaceutically acceptable base salt thereof, wherein R is fluorine, chlorine, iodine, fluoromethyl, chloromethyl, bromomethyl, 1 to 4 carbon alkoxy or 1 to 4 carbon alkylthio, n is an integer from 0 to 2 and R^ is hydrogen , ester-forming residues which are readily hydrolyzable in vivo, or penicillin carboxy-protecting groups, with the proviso that when R is alkylthio, chlorine or iodine, n is an integer from 0 to 1.

A preferred group of β-lactamase inhibitors are those where n is 0 and R 1 is hydrogen. Within this group, the compounds where R is chlorine or iodine are particularly preferred.

Another group of preferred compounds are those where n is 1 and R 1 is hydrogen. Particularly preferred within this group are compounds where R is chlorine or iodine.

A third group of compounds which are preferred are those where n is 0 and R^ is a penicillin-carboxy-protecting group, said group consisting of a) -PR2R3where R2 and R3 are each alkyl of 1 to 3 carbon atoms, alkoxy of 1 to 3 carbon atoms or phenyl,

b) 3,5-di-t-butyl-4-hydroxybenzyl,

c)~CH 2 -Y where Y is -C(O)R 4 where R 4 is phenyl or alkyl

with 1 to 3 carbon atoms, cyano or carboalcoxy with 2 to 4

carbon atoms,

d) -N=CHR5where R5 is phenyl or alkyl with 1 to 3 carbon atoms, e) -CH(COCH3)C02R6where R& is alkyl with 1 to 4 carbon atoms, f) -CR^RgRg where R? and Rg is each hydrogen, phenyl or methyl, and Rg is phenyl, 4-methoxyphenyl or methyl with the proviso that when R? and Rg is each methyl, Rg is methyl, and when Ry and Rq are each hydrogen and Rg is phenyl, R is fluoro, iodo, fluoromethyl, chloromethyl, bromomethyl, 1 to 4 carbon alkoxy, or 1 to 4 carbon alkylthio. g) -Si(CH3)3 and -Si(CH3)2t-C4Hg, or h) -SnR16R17R1Q where R16 and R17 and R^8 are each alkyl with

1 to 5 carbon atoms, phenyl or benzyl.

Particularly preferred within this group are such compounds where R^ is tri-n-butyltin and R is chlorine, where R^ is trimethylsilyl and R is chlorine and where R^ is 4-methoxybenzyl and R is iodine.

A fourth group of preferred compounds are those where R^ is an ester-forming residue which is readily hydrolyzable in vivo, and said group consists of alkanoyloxymethyl with 3 to 6 carbon atoms, l-(alkanoyloxy)ethyl with 4 to 7 carbon atoms, 1-methyl -1-(Alkanoyloxy)ethyl with 5 to 8 carbon atoms, Alkoxycarbonyloxymethyl with 3 to 6 carbon atoms, 1-(Alkoxycarbonyloxy)ethyl with 4 to 7 carbon atoms, 1-Methyl-1-(Alkoxycarbonyloxy)ethyl with 5

to 8 carbon atoms, 3-phthalidyl, 4-crotonolactonyl and T-butyro-lacton-4-yl. Particularly preferred within this group are such

compounds where R is chlorine, R^ is pivaloyloxymethyl and n is 0, and where R^ is pivaloyloxymethyl, R is iodine and n is 0.

The present invention also relates to a pharmaceutical preparation which is useful in the treatment of bacterial infections in mammals, and which comprises a pharmaceutically acceptable carrier, a β-lactam antibiotic and a compound of the formula

or a pharmaceutically acceptable base salt thereof, wherein R is fluoro, chloro, iodo, fluoromethyl, chloromethyl, bromomethyl, 1 to 4 carbon alkoxy or 1 to 4 carbon alkylthio, n is an integer from 0 to 2, and R^ is hydrogen or an ester-forming residue which is readily hydrolyzable in vivo, with the proviso that when R is alkylthio, n is an integer from 0 to 1. Preferred within this group of compounds are those where R^2 is hydrogen or an ester- forming residue which is readily hydrolyzable in vivo and selected from alkanoyloxymethyl with 3 to 6 carbon atoms, l-(alkanoyloxy)ethyl with 4 to 7 carbon atoms, 1-raethyl-l-(alkanoyloxy)ethyl with 5 to 8 carbon atoms, alkoxycarbonyloxymethyl with 3 to 6 carbon atoms, 1-(Alkoxycarbonyloxy)ethyl with 4 to 7 carbon atoms, 1-methyl-1-(Alkoxycarbonyloxy)ethyl with 5 to 8 carbon atoms, 3-phthalidyl, 4-crotonolactonyl and T-butyrolacton-4-yl , and n is 0, and said β-lactam antibiotic is selected from penicillins and cephalosporins. Particularly preferred are compounds where R is chlorine or iodine and R^2Q£hydrogen and where R is iodine or chlorine and R^ is pivaloyloxymethyl. This invention also relates to a method for increasing the effectiveness of a /3-lactam antibiotic, in a mammal, which comprises co-administering to said mammal an amount which effectively increases the /3-lactam antibiotic effect, of a compound with the formula

or a pharmaceutically acceptable base salt thereof wherein R, n and R^2 are as. previously stated. Preferred by this invention

are compounds where n is 0 and R 13 is hydrogen or an ester-forming residue which is readily hydrolyzable in vivo, as previously indicated, and said β-lactam antibiotics are selected from penicillins and cephalosporins. Particularly preferred in this method are compounds where R 3 is hydrogen and R is chlorine or iodine and R 13 is Piva 3 -yloxymethyl and R is iodine or chlorine.

The present invention also includes compounds with the formula

Is if i 1 is substantially free of the 6-ot-brora epimer, or a pharmaceutically acceptable base salt thereof, where R 4 is hydrogen, ester-forming residues which are readily hydrolyzable in vivo, or penicillin carboxy protecting groups. Particularly preferred is the crystalline free acid where R 4 is hydrogen, and the crystalline sodium urasalt thereof.

A preferred group of compounds are those where R 4 is a penieillin carboxy protecting group consisting of a) -PRgllj where R 2 and R 3 are each alkyl of 1 to 3 carbon atoms, alkoxy of 1 to 3 carbon atoms or phenyl,

b) 3,5-di-t-butyl-4-hydroxybenayl,

c) -CELj-Y where Y is -C(O)R 4 where R 4 is phenyl or alkyl

with 1 to 3 carbon atoms, eyano or carboalkoxy with 2 to 4

carbon atoms,

d) -EP^HR where R5 is phenyl or alkyl with 1 to 3 carbon atoms, e) -CH-(GOCH 3 )CO 2 Kg where Rg is alkyl with 1 to 4 carbon atoms, f) -CRyRgR^where Ry and Rg are each hydrogen, phenyl or methyl, and Rg is phenyl, 4-iaethoxyphenyl or methyl with the proviso that when R- and Rg are each methyl, Rg is methyl,

g) -Si(GH3)3 and -Si(CH3)2t-C4H9,

h)""SnRi6RX7R18llvor Ri6°<9><R>17°S R18each is a^^Y1 of 1 to 5 carbon atoms, phenyl or benzyl. Particularly preferred within this group are such compounds where R 4 is tri-n-butyltin and where R 14 is trimethylsilyl. Another group of preferred compounds are those where R14 is an ester-forming residue which is easily hydrolyzable in vivo, and said group consists of alkanoyloxymethyl with 3 to 6 carbon atoms, 1-(alkanoyloxy)ethyl with 4 to 7 carbon atoms, 1-methyl- 1-(Alkanoyloxy)ethyl of 5 to 8 carbon atoms, Alkoxycarbonyloxymethyl of 3 to 6 carbon atoms, 1-(Alkoxycarbonyloxy)ethyl of 4 to 7 carbon atoms, 1-Methyl-1-(Alkoxycarbonyloxy)ethyl of 5 to 8 carbon atoms, 3-Phthalidyl , 4-crotonolactonyl and 'N-butyrolacton-4-yl. Particularly preferred within this group is the compound where R14 is pivaloyloxymethyl. Included within the present invention is also a pharmaceutical preparation for the treatment of bacterial infections in mammals, which comprises a pharmaceutically acceptable carrier, a β-lactam antibiotic and a compound of the formula

substantially free of the 6-α-bromo epimer, or a pharmaceutically acceptable base salt thereof, wherein R 1 is selected from the group consisting of hydrogen and ester-forming residues which are light. hydrolyzes only in vivo, and n is an integer from 0 to 2. Preferred within this group of compounds are those where R^2 is hydrogen or an ester-forming residue which is readily hydrolyzable in vivo selected from alkanoyloxymethyl with 3 to 6 carbon atoms, 1-(alkanoyloxy)ethyl with 4 to 7 carbon atoms, 1-methyl-1-(alkanoyloxy)ethyl with 5 to 8 carbon atoms, alkoxycarbonyloxymethyl with 3 to 6 carbon atoms, 1-(Alkoxycarbonyloxy)ethyl with 4 to 7-carbon atoms, 1-methyl-1-(alkoxycarbonyl-oxy)ethyl having 5 to 8 carbon atoms, 3-phthalidyl, 4-crotono-la jktbnyjTl and T-butyrolacton-4-yl and n is 0, and said/3- lactam antibiotics are selected from penicillins and cephalosporins. Particularly preferred are the compounds where R 1 is hydrogen and n is 0, and the sodium salt thereof. This invention also includes methods of increasing the effectiveness of a β-lactam antibiotic in a mammal, which comprises co-administering to said mammal a β-lactam antibiotic compound of the formula

substantially free of the 6-α-bromo epimer, or a pharmaceutically acceptable base salt thereof, where n and R 1 are as previously indicated. Preferred within this invention are compounds where n is 0 and R^2®r is hydrogen or an ester-forming residue which is easily hydrolyzable in vivo, as previously defined, and where said Æ-lactam antibiotic is selected from penicillins and cephalosporins. Particularly preferred in this method are compounds where R^ 2 is hydrogen and where R^3 is pivaloyloxymethyl. The present invention also includes a method for the preparation of a compound of the formula

where R is fluorine, chlorine, bromine, iodine, alkoxy with 1 to 4 carbons. atoms or alkylthio with 1 to 4 carbon atoms, n is 0 to 2 and R^3 is hydrogen or ester-forming residues which are readily hydrolyzable in vivo, which comprises reacting a compound of the formula

where X is chlorine, bromine or iodine, and Rig are ester-forming residues

which are readily hydrolyzable in vivo or conventional penicillin carboxy protecting groups, with an organotin monohydride at ca. 0-UO°C, followed by removal of Rlg when it is

a conventional penicillin carboxy protecting group, with the proviso that when R 2 g is a conventional penicillin carboxy protecting group, n is 6 to 1.

A preferred feature of the present method is the use of one organotin monohydride with the formula

<HSnR>16<R>17<R>18

where R 16 # R 17 and R 1 Q are each alkyl of 1 to 5 carbon atoms,

phenyl or benzyl.

A further preferred feature of this method is the use of compounds where R 1 is a conventional penicillin carboxy-protecting group selected from a) -PR 2 R 3 where R 2 and R 3 are alkyl of 1 to 3 carbon atoms, alkoxy of 1 to 3 carbon atoms or phenyl,

b) 3,5-di-t-butyl-4-hydroxybenzyl,

c) -CH2~Y where Y is -C(0)R4where R4 is phenyl or alkyl

with 1 to 3 carbon atoms, cyano or carboalkoxy with 2 to 4

carbon atoms,

d) -N=CHR5 where R5 is phenyl or alkyl with 1 to 3 carbon atoms, e) -CH(COCH3)CO2R6 where R& is alkyl with 1 to 4 carbon atoms, f) -CR?RgRg where R7 and Rg are each hydrogen, phenyl or methyl and Rg is phenyl, 4-methoxyphenyl or methyl, with the proviso that when R^ and Rg are each methyl, Rg is methyl,

g) -Si(C<H>3)3 and -Si(CH3)2t-C4Hg,

h)~SnRi6Ri7Ri8where R16'<R>i7 °9Ri8each is alkYl with<3

1 to 5 carbon atoms, phenyl or benzyl.

Particularly preferred is the process where R 2 is a conventional penicillin carboxy protecting group

-SnR^6R17Rlg where R^g, R^7- and R^g are each n-butyl, R^5 and X are each bromine, n is 0, and the organotin monohydride is tri-n-butyltin hydride, and said protecting group is removed by aqueous hydrolysis. Particularly preferred is also the method where <R>19 is a conventional penicillin carboxy-protecting group

~S<n>R16R17<R>18 where R16' R17 °g R18 is each n-butyl, R15 is chlorine, X is iodine, n is 0 and the organotin monohydride is tri-n-butyltin hydride, where the protecting group is removed by aqueous hydrolysis. Particularly preferred is the process wherein R,_ is a conventional penicillin carboxy protecting group -Si(CH3>3, R15 and X are each bromine or wherein R15 is chlorine and X is iodine, n is 0 and the organotin monohydride is tri -n-butyltin hydride, where said protecting group is removed by aqueous hydrolysis. Particularly preferred is also the method where Rlg is a conventional penicillin carboxy protecting group -CR7R8Rg where R? and RQ are each hydrogen and Rg is 4- methoxyphenyl, R15°9x is each iodine, n is 0 and the organotin monohydride is tri-n-butyltin hydride, said protecting group being removed by hydrolysis.

A further preferred feature of this method is the use of compounds where R 2 is an ester-forming residue which is light. hydrolyzable in vivo, selected from alkanoyloxymethyl with from 3 to 6 carbon atoms, l-(alkanoyloxy)ethyl with from 4 to 7 carbon atoms, 1-methyl-l-(alkanoyloxy)ethyl with from 5 to 8 carbon atoms, alkoxycarbonyloxymethyl with from 3 to 6 carbon atoms, 1-(Alkoxycarbonyloxy)ethyl with from 4 to 7 carbon atoms, 1-methyl-1-(Alkoxycarbonyloxy)ethyl with from 5 to 8

carbon atoms, 3-phthalidyl, 4-crotonolactonyl and Y-butyrolacton-4-yl. Particularly preferred is the process where R^g is pivaloyloxymethyl, and X is each bromine, n is 0 and the organotin monohydride is triphenyltin hydride, the process where R^g is pivaloxymethyl, R^^ is chlorine and X is iodine, n is 0 , and the organotin monohydride is tri-n-butyltin hydride, and the process where R^g is pivaloyloxymethyl, R^g and X are each iodine, n is 0.<p>g the organotin monohydride is tri-n-butyltin -hydride.

The process according to the present invention is unique in that it allows the synthesis of a large number of 6-/3-penicillanic acids and derivatives thereof which are essentially free of the corresponding 6-α-epimer, and gives -6-substituted penicillanic acids which are composed of at least 75% of Ø-épimer. In many cases, the content of the desired Ø-epimer is as high as 99.5%. Since the α-epimer i. is essentially inactive as a β-lactamase inhibitor, it is essential for this application that the products have as high an β-epimer content as possible. Products containing large amounts of the α-epimer must be used in larger doses to provide inhibition of the β-lactarnase enzymes and strengthening of β-lactam antibiotics. The larger doses of these materials can lead to toxicity problems for mammalian verteh.

Most of the biologically active compounds according to the present invention are produced by the method according to the present invention which is prepared in the following scheme:

where X, R 15/ n» R 19' R 16' R 17' R 18 and R 13 are as previously indicated.

Usually, the reduction is carried out simply, without the use of a solvent, or it can be carried out in a solvent provided that this solvent is a reaction-inert solvent which appreciably dissolves the reactants without reacting to any great extent with the reactants or the product under the reaction conditions. When a solvent is used, it is preferred that this solvent is an aprotic solvent,

immiscible with water and with a boiling and freezing point compatible with the reaction temperatures. Such solvents or mixtures thereof include aromatic solvents such as benzene or toluene.

When the aforementioned reaction is carried out without a solvent, the reactants are carefully mixed and heated to the prescribed reaction temperature.

The molar ratio between the starting penicillanic acid derivative and the organotin monohydride is not critical in the present process. Use of a slight excess of the stannous hydride, up to as much as 10% above an equimolar amount, helps to complete the reaction, and does not entail any serious problem when isolating the desired product in purified form.

The reaction time naturally depends on the concentration, reaction temperature and reactivity of the starting reagents. When the present process is carried out without a solvent, a reaction temperature of 60-100°C is used. Under these temperature conditions, turnover is usually completed in 5-8 hours. When a solvent is used, a reaction temperature of 80-100°C is used and 4-6 hours are required to; complete the turnover.

The reaction time and temperature can be clearly reduced by carrying out the reaction under ultraviolet radiation. Under these conditions, the turnover is initiated with a free radical initiator,

such as azobisisobutyronitrile, and it is carried out under cooling so that a temperature of approx. 15-25°C. The reaction time under these conditions is from approx. 15 minutes to several hours.

The preferred reaction temperatures are those which permit

that the turnover takes place at a practical speed without resulting in thermal degradation of the starting reagents or products in this process. Accordingly, temperatures of 0-100°C are applicable.

Although the order of addition of the reactants is not critical, it is preferred that the organotin monohydride be added to the 6,6-disubstituted penicillanic acid derivative. In this preferred way, the bis-dehalogenation, when a 6,6-dihalopenicillanic acid derivative is used, is reduced to a minimum.

For the compounds of the above formulas, a broken line indicates that a substituent attached to the bicyclic penicillanic acid core lies below the plane of this core, and is said to be in the " configuration. Solid line attachment of a substituent to this nucleus shows that the substituent is fixed above the plane, and is referred to as the P configuration. The wavy line is intended to denote two epimers or mixtures thereof.

The organotin monohydrides used as reactants in the present process are prepared by methods known to those skilled in the industry. Such as are not commercially available can be prepared by the methods outlined by Hayashi et al., J. Organometal. Chem., 10.81 (1967).

The biologically active compounds according to the present

The biologically active compounds according to the present invention that are not synthesized by the aforementioned method of the present invention are prepared according to the following scheme:

where R, is the penicillin carboxy-protecting group, n is as previously indicated, and R is fluoromethyl, chloromethyl or bromomethyl.

After the above reaction, the carboxy-protecting group can be removed to provide the compounds where R^ is hydrogen

The 6/3-hydroxymethyl substituent is replaced by fluoromethyl by a reaction with the fluorinating agent diethylaminosulfur trifluoride. The reaction is carried out in a reaction-inert solvent which does not react appreciably with the reactants or the product under the reaction conditions. It is preferred that such solvents are aprotic solvents which can dissolve the starting reagents, are immiscible with water and have boiling and freezing points which are compatible with the reaction conditions. Such solvents include chlorinated hydrocarbons such as methylene chloride.

Equimolar amounts of the fluorinating agent and the penicillanate are usually used together with two moles of a tertiary amine, such as pyridine.

The preferred reaction temperatures are those which allow the turnover to take place at a practical rate. Accordingly, temperatures of -50 to -78°C are applicable.

The reaction time naturally depends on the concentration, reaction temperature and reactivity of the starting reagents. When the reaction is carried out at -78°C, it is usually substantially complete after 45-60 minutes.

After completion, water is added to quench the reaction mixture, and the product is then isolated from the organic phase and purified, if necessary by chromatography on silica gel.

Preparation of compounds of formula III where R is chloromethyl or bromomethyl is carried out by treating the necessary 6/3-hydroxymethyl penicillanate with triphenylphosphine and respectively carbon tetrachloride or carbon tetrabromide.

Experimentally, one mole of the penicillanate is reacted with two moles of triphenylphosphine in an excess of the appropriate carbon tetrahalide. In cases where it is not desired to use the carbon tetrahalide as solvent and reactant, a co-solvent can be used. It is preferred that the co-solvent is miscible with the carbon tetrahalide and is inert to reaction with either the starting reagent or the product of the reaction. A preferred co-solvent is methylene chloride.

The preferred reaction temperature is approx. 0-5°C, with a

corresponding reaction time of approx. 1-3 hours.

After completion of the reaction, the product, which can be isolated by removing the solvent or precipitation of the product by adding a solvent in which the product has little or no solubility, is purified, if necessary by chromatography on silica gel.

The synthesis of compounds of formula III is not carried out with the free acids, but with compounds where the carboxy group is modified with a penicillin carboxy protecting group, as previously mentioned.

Moreover, the reaction of 6,6-disubstituted penicillanic acids to the corresponding 6-0-substituted compounds is not carried out with the free acids, but is also carried out with a derivative of said acid as defined by R^g- These types of derivatives by The 3-carboxy group in the penicillanic acid is known to those skilled in the industry and is relatively easy to prepare. According to the method according to the present invention, certain of these derivatives, i.e. those which are conventional penicillin carboxy-protecting groups, can be removed from the carboxy part and provide the production of the free acid of formula II (where R 1 is hydrogen). As one skilled in the art will readily appreciate, the removal of a specific protecting group must be compatible with the reactivity of the substituent at the 6-0 position. Consequently, removal of a benzyl protecting group from a penicillanic acid containing a 6-/3-halogen or halomethyl substituent by hydrogenolysis may provide a less than optimal yield of the desired product due to the propensity of halogens to dehalogenate under such reaction conditions ;

The first of these conventional penicillin carboxy protecting groups is the phosphine ester. According to the method in BRD official publication 2,218,209, the appropriate 6/3-hydroxymethyl or 6,6-disubstituted penicillanic acid, such as a triethylamine salt, is reacted with a dialkyl or dialkyl chlorophosphine to

provide a desired starting reagent for the present process. At the end of the reaction between said reagent and a halogenating agent or an organotin monohydride, the protecting group is removed from the 6-/3-substituted penicillin by the addition of water to provide the products where R^ is hydrogen.

The second protecting group is the 3,5-di-t-butyl-4-hydroxybenzyl ester. This is conventionally produced from the necessary...: reversible 6/3-hydroxymethyl- or 6,6-disubstituted penicillanic acid by following the procedure in BRD official publication 2,033,493, which includes reacting the aforementioned penicillanic acid, so

as a triethylamine salt, with ethyl chloroformate, and a subsequent reaction of the resulting mixed anhydride with 3,5-di-t-butyl-4-hydroxybenzyl alcohol. After the reaction of the starting reagent with a carbon generator or an organotin monohydride in the present process, the protecting group is removed by aqueous hydrolysis at pH 8.0. •

The third type of protecting group which is suitable in the method according to the present invention is such compounds where R 2 g is -CH 2 Y where Y is as previously indicated. These 6,8-hydroxymethyl and 6,6-disubstituted penicillanic acid esters are prepared by alkylating the corresponding penicillanic acid triethylamine salt with a suitable halide, following the procedure in Acta. Chem. Scand.., 2_1, 2210 (1967). After the reaction of the aforementioned reagent with a halogenating agent or an organotin monohydride, the protecting group is removed, preferably with potassium thiophenoxide.

The fourth type of protecting group in this series, where R-^g is -N=CHR5. and where R 5 is as previously indicated, is incorporated into 6/3-hydroxymethyl or 6,6-disubstituted penicillanic acid by following the procedure' in J. Chem. Soc, 1917 (1971c), which involves reacting the mixed anhydride, formed from the necessary 6,8-hydroxymethyl or 6,6-disubstituted penicillanic acid and ethyl chloroformate, with an appropriate aldehyde oxime. After the reaction of the 6/3-hydroxymethyl compounds with a halogenating agent or the 6,6-disubstituted compounds with stannous hydride in the present process, the protecting group is removed from the 6-0-substituted penicillanic acid by treatment with potassium thiophenoxide.

The fifth type of protecting group is an ester derived from acetodiacetic acid esters. Procedures for introducing this type

protecting group on a penicillin carboxy protecting group is described by Ishimaru et al., Chemistry Letters, 1313 and 1317

(1977) , and involves treatment of a sodium salt of a 6/3-hydroxymethyl or 6,6-disubstituted penicillanic acid with an appropriate alkyl-α-haloacetoacetate. After the reaction of this product with a halogenating reagent or an organotin monohydride, the protecting group is removed from the 6-/3-penicillan derivative by treatment with an aqueous solution of sodium nitrite.

There is a sixth type of protecting group where R^g is -CRyRgRg

can be prepared in a number of ways, and all details are given in the chemical literature. The preferred synthesis involves starting with known 6-Æ-aminopenicillanic acid esters followed by replacing the 6-amino portion with a 6-diazo group, as discussed e.g. by Cama et al., J. Am. Chem. Soc, 94, 1408 (1972) and Harrison et al., J. Chem. Soc. (Perkiri I), 1772 (1976). After the reaction of the 6,6-disubstituted penicillanic acid, which has a conventional penicillin carboxy protecting group at the 3-carboxy group, with an organotin monohydride, the protecting group is removed. When two or more of the substituents R^, Rg and Rg are phenyl or if Rg is 4-methoxyphenyl or if R^, Rg and Rn are each methyl, the protecting group can be removed by treatment with trifluoroacetic acid. This removal method is compatible with other possible substituents in the 6-/3-position. When R? or RQ is methyl or R? and RQ is hydrogen and Rg is phenyl, said protecting groups can be removed by treatment with trimethyl-• ~ silyl iodide, as indicated by Jung et al., J. Am. Chem. Soc, 99, 968 (1977). Alternatively, these groups can be removed by hydrogenolysis, provided that the 6-/3-substituent is not a halogen or an alkylthio moiety.

The preparation of the required 60-hydroxymethylpenicillanates can be carried out by reacting the corresponding 60-hydroxymethylpenicillanic acid as an activated anhydride with a suitable alcohol HOR^RgRg or by alkylating a salt of said acid with R-jRgRgC halide. After treatment of the 6,3-hydroxymethyl penicillinate with the appropriate halogenating reagent, the protecting group is removed as indicated above.

The seventh type of protecting group is one trimethylsilyl or dimethyl-t-butylsilyl ester which is developed in situ by reacting a triethylamine salt of a 6,6-disubstituted penicillanic acid and an appropriate silyl chloride, according to the procedure set forth in Ann., 673, 166 (1964). After the reaction of the protected 6,6-disubstituted penicillanic acid with the organotin monohydride, the protecting group is removed by aqueous hydrolysis.

The eighth protecting group proposed by the present invention and discussed earlier is that where .R^g is -SnR^R^R^g, and where R^g#R-^y °9" R^g is as previously stated. The tin ester protecting group is formed by adding one molar amount of bis(tin)oxide to two moles of the free 6,6-disubstituted penicillanic acid according to Chem. Ind. 1025 (1976). After completion of this procedure , the protecting group is removed by aqueous hydrolysis.

A penicillin carboxy-protecting group which is particularly useful in the synthesis of compounds of formula II, wherein R 1 , . is said alkylthio, n is 0 or 1 and R 1 is hydrogen, is trichloroethyl. This group is introduced onto the carboxy group in the appropriate 6,6-disubstituted penicillanic acid using the method indicated in BRD patent document 1,937,962. Conversion of said disubstituted penicillanic acid trichloroethyl ester to a 6-halo-6-alkylthiopenicillanic acid trichloroethyl ester or a -sulfoxide, according to the method described later, followed by. treatment with an organotin monohydride results in the production of a 6-/3-alkylthiopenicillanic acid trichloroethyl ester or a -sulfoxide. Removal of the protecting trichloroethyl moiety to provide a compound of formula II wherein R^ is hydrogen is accomplished by treatment with zinc dust in a buffered solution.

As one skilled in the art will appreciate, there are numerous other unmentioned penicillin carboxy protecting groups which are useful in carrying out the present process for preparing compounds of the above formula where R 3 is hydrogen. The use of such protective groups in the present process, although not exhaustively illustrated, is considered to be within the broad scope of the present invention. The 6-/3-substituted penicillanic acids containing conventional penicillin carboxy-protecting groups are valuable intermediates leading to the corresponding free acids.

When R, 3 is an ester-forming residue which is readily hydrolyzable in vivo in a compound of formula II, it is a group which

is conceptually derived from an alcohol with the formula R13~OH, so that the part COOR^3 in such a compound with formula II represents an ester group. Moreover, R^3 is of such a nature that the group COOR13 is easily cleaved in vivo to release a free carboxyl group (COOH). That is, R^3 is a group of the type that when a compound of formula II, where R^3 is an ester-forming residue that is easily hydrolyzable in vivo, is exposed to mammalian blood or tissue, a compound of formula II where R^3 is hydrogen. The groups R^3 are known in the penicillin industry. In most cases, they improve the absorption properties of the penicillin compound. Moreover, R 3 should be of such a nature that it imparts pharmaceutically acceptable properties to a compound of formula II, and releases pharmaceutically acceptable fragments when this is cleaved in vivo.

As indicated above, the group R^3 is known and readily identified by those skilled in the penicillin industry, as discussed in BRD off. font 2,517,316; Typical groups for R^3 are 3-phthalidyl,

4-crotonolactonyl, T-butyrolacton-4-yl, alkanoyloxyalkyl and alkoxycarbonyloxyalkyl. Preferred groups for R 3 are, however, alkanoyloxymethyl with from 3 to 6 carbon atoms, 1-(alkanoyl-doxy)ethyl with from 4 to 7 carbon atoms, 1-methyl-1-(alkanoyloxymethyl with from 5 to 8 carbon atoms), alkoxycarbonyloxymethyl with from 3 to 6 carbon atoms, 1-(Alkoxycarbonyloxy)ethyl with from 4 to 7. carbon atoms, 1-methyl-1-(Alkoxycarbonyloxy)ethyl with from 5 to 8 carbon atoms, 3-phthalidyl, 4-crotonolactonyl and V-butyrolactone-4- yl.

Compounds of formula II wherein R^3 is an ester-forming residue which is readily hydrolyzable in vivo can be prepared directly from a compound of formula II wherein R^3 is hydrogen, by esterification. The specific method chosen will naturally* ; depend on the exact structure of the ester-forming residue, but a suitable method can be readily chosen by one skilled in the art. In those cases where R 13 is selected from the group consisting of 3-phthalidyl, 4-crotonolactonyl, T-butyrolacton-4-yl, alkanoyloxyalkyl and alkoxycarbonyloxyalkyl, it can be prepared by alkylating a compound of formula II where R 3 is hydrogen, with a 3 -phthalidyl halide, a 4-crotonolactonyl halide,

a y<->butyrolacton-4-yl halide, an alkanoyloxyalkyl halide or an alkoxycarbonyloxyalkyl halide. The term "halide" is intended to include derivatives of chlorine, bromine and iodine. The reaction is conveniently carried out by dissolving a salt of the compound of formula II where R^3 is hydrogen, in a suitable, polar, organic solvent, such as N,N-dimethylformamide, and then adding approx. one mole equivalent of the halide. When the reaction has progressed to essentially complete completion, the product is isolated by standard techniques. It is often sufficient to simply dilute the reaction medium with an excess of water, and then: extract the product into a water-immiscible organic solvent and then recover the product by solvent evaporation. Salts of the starting material which are usually used are alkali metal salts, such as sodium and potassium salts, and tertiary amine salts, such as triethylaraine, N-ethylpiperidine, N,N-dimethylaniline and N-methylmorpholine salts. The conversion is carried out at a temperature in the range from approx. 0 to 100°C, and usually at approx. 25°C. The duration required to reach complete turnover varies according to a number of factors, such as the concentration of the reactants and the reactivity of the reactants. Thus, when considering the halogen compound, the iodide reacts faster than the bromide, which in turn reacts faster than the chloride.

In fact, when a chlorine compound is used, it is sometimes advantageous to add up to one molar equivalent of an alkali metal iodide. This has the effect of speeding up turnover. Taking full account of the preceding factors, it is common to use turnover times of from 1 to 24 hours.

Alternatively, compounds according to the present invention with formula II where R^3 is an ester-forming residue which is easily hydrolyzable in vivo can be prepared from compounds with formula I where R^g is comprised of said ester-forming groups, by the method in according to the present arrangement.

The starting reagents of formula I wherein R^g is an ester-forming residue which is readily hydrolyzable in vivo selected from

the group consisting of 3-phthalidyl, 4-crotonolactonyl, T-butyrolacton-4-yl, alkanoyloxyalkyl and alkoxycarbonyloxyalkyl, can be prepared by alkylation of a compound of formula I where R15'X °9* n is as indicated and where Rig is hydrogen, with a phthalidyl halide, a crotonolactonyl halide, a T-butyrolacton-4-yl halide, an alkanoyloxyalkyl halide or an alkoxycarbonyloxyalkyl halide. The reaction is carried out by dissolving the efc salt of the compound of formula I, where R-^g is hydrogen, in a suitable, polar, organic solvent, such as N,N-dimethylformamide, and then adding approx. one mole equivalent of the halide. When the turnover has progressed to essentially complete perfection, the product is isolated using standard techniques. It is often sufficient simply to dilute the reaction medium with an excess of water and then extract the product into a

water-immiscible organic solvent, and then recover the product by evaporation of the solvent. Salts of the starting material commonly used are alkali metal salts, such as sodium and potassium salts, and tertiary amine salts, such as triethylamine, N-ethylpiperidine, N,N-dimethylaniline and N-methylmorpholine salts. The turnover takes place at a temperature in the range from approx. 0 to 100°C, and usually at approx. 25°C. The time required to reach complete turnover varies according to a number of factors, such as the concentration of the reactants and the reactivity of the reactants. Thus, when considering the halpgenide compound, the iodide reacts faster than the bromide, which in turn reacts faster than the chloride. In fact, it is sometimes advantageous, when using a chlorine compound, to add up to one molar equivalent of an alkali metal iodide. This has the effect of speeding up turnover. With complete consideration of the preceding factors, reaction times of from approx. 1 to approx. 24 hours.

An alternative method for the preparation of the starting reagents for the present process, of formula I where R^g is said ester-forming residue, is by diazotization of a suitable 6-/3-aminopenicillanic acid ester, and reaction of the resulting diazopenicillanic acid ester to obtain the desired 6,6-disubstituted penicillanic acid ester as described later. *

Compounds of formula I where Rly/X and n are as indicated

and R^g is said alkylthio, is most conveniently prepared from the corresponding 6,6-dihalopenicillanic acid ester, preferably the 6,6-dibromopenicillanic acid ester. Said 6,6-dihalogenopenicillanic acid ester is converted into a 6-bromo-6-Grignard derivative by reacting the 6,6-dihalogen compound with approx. an equimolar amount of t-butyl magnesium chloride in anhydrous tetrahydrofuran at -75°C. The Grignard intermediate is then reacted, without isolation, with a methylalkylthiosulfonate to give, by hydrolysis and purification, the desired 6-halo-6-alkylthiopenicillanic acid ester of formula I wherein X and n are as indicated, R-j .5 is alkylthio and

R^g is an ester-forming residue that is readily hydrolyzable in vivo or a protecting group.

Compounds according to the present invention of formula II where R 1 is as indicated, with the exception of alkylthio, and R 2 is as indicated and n is an integer of 1 or 2, can be prepared by direct oxidation of compounds of formula II where R ^j. are as indicated, with the exception of alkylthio, R 1 is as indicated and n is 0.

When a compound of formula II as set forth above, wherein

n is 0, is oxidized to the corresponding compound of formula II where n is 2 using a metal permanganate, the reaction is usually carried out by treating the compound of formula II with from 1.0 to about 5 mole equivalents of the permanganate, and preferably approx. 2 molar equivalents of the permanganate, in a suitable solvent system. A suitable solvent system is one that does not adversely affect either the starting materials or the product, and water is usually used.

If desired, a co-solvent can be added which is miscible with water but which will not react with the permanganate, such as tetrahydrofuran. The reaction is usually carried out at a temperature in the range from approx. -20 to approx. 50°C, and preferably at approx. 0°C. At approx. 0°C, the turnover is usually substantially completed within a short period, e.g. within one hour. Although the reaction can be carried out under neutral, basic or acidic conditions, it is preferred to operate under essentially neutral conditions in order to avoid cleavage of the β-lactam ring cyst of the compound of formula II. In reality, it is often advantageous to buffer the pH in the reaction medium to near neutral. The product is extracted by conventional techniques. Any excess of permanganate is usually cleaved using sodium bisulphite, and the product is isolated by ordinary solvent extraction, after previous acidification of the aqueous layer.

When a compound of formula II, as previously indicated, where n is 0, is oxidized to the corresponding compound of formula II where n is 2, using an organic peroxy acid, e.g. a peroxycarboxylic acid, the reaction is usually carried out by treating the compound of formula II with from about 2 to approx. 4 mole equivalents, and preferably approx. 2.2 equivalents,

of the oxidizing agent in a reaction-inert organic solvent. Typical solvents are chlorinated hydrocarbons, such as dichloromethane, chloroform and 1,2-dichloroethane, and ethers, such as diethyl ether, tetrahydrofuran and 1,2-dimethoxyethane. The reaction is usually carried out at a temperature of from -20 to approx. 50°C, and preferably at approx. 0°C. At approx. 25°C, turnover times of approx. 2 to approx. 16 hours. The product is usually isolated by removal from the solvent by evaporation in vacuo. The product can be cleaned by conventional methods, which are well known in the industry.

Compounds of formula II where R 5 is as indicated é with the exception of said alkylthio, R 13 is hydrogen and n is 1, can also be prepared by removing the penicillin-carboxy protecting group as indicated by Rig in the compounds of formula I. It it is only required that said protecting group is: i) . stable during oxidation of the compounds of formula I where R^g is said protecting group, and R^,. and X is as indicated,

ii) removable from the compounds of formula II, using conditions in which the β-lactam remains substantially intact, and

iii) removable from compounds of formula II, under conditions under which epimerization of the /3-substituent is essentially avoided.

Compounds of formula II where R 15 is as indicated, with the exception of alkylthio, R 3 is hydrogen and n is 2, cannot be practically prepared by removal of the penicillanic protecting group as indicated by Rig. Said compounds, with the exception of those where R,_ is alkylthio, are best prepared by direct oxidation

tion of such congeners where is hydrogen.

In a similar way, oxidation of the compounds mentioned above where h is 0, to corresponding compounds where n is 1, can be carried out in exactly the same way as described above, except that half as much oxidizing agent is used. The sulfoxides, as described in the present invention, are intended to include both the ω- and ω-epimers and mixtures thereof.

Such compounds of formula II where R^ is as indicated,

n is an integer of 1 or 2 and R^j. is alkylthio, cannot be formed in any practical way by direct oxidation of compounds of formula II where R^ is as indicated, n is 0 and R^,. is alkylthio. Such oxidations often lead to mixtures of products which include those oxidized on the alkylthio moiety, and careful separation and purification of the desired product is required. In the preparation of said products, it is preferred that they are produced by an initial oxidation, under the previously described conditions, of the 6,6-dihalopenicillanic acid and its derivatives to provide the corresponding 6,6-dihalopenicillanic acid sulfones or sulfoxides and esters derivatives thereof. The conversion of the resulting sulfones and sulfoxides into the corresponding 6-halo-6-Grignard reagents is carried out by the previously described method, and likewise the conversion of said Grignard reagents into the appropriate 6-halo-6-alkylthiopenicillanic acid sulfone or sulfoxide and derivatives hence. The subsequent reaction of these products with an organotin monohydride by the previously described present process provides the useful products according to the present invention^

In a similar way, the production of compounds is included. the formula

where n is as previously indicated and R^ is an ester-forming residue which is readily hydrolyzable in vivo, and R is fluoromethyl, chloromethyl or bromomethyl, most conveniently prepared by treating ay the appropriate 60-hydroxymethyl penicillanate ester with the required .

halogenation reagent, as previously described. Said 6/3-hydroxymethylpenicillanate ester is, in turn, synthesized by alkylation of the corresponding 6/3-hydroxymethylpenicillanic acid sulfoxide or sulfone in a manner that has also been described previously.

As previously stated, compounds of formula IV where R,- is an ester-forming residue which is easily hydrolyzable in vivo, are converted in vivo to compounds where R,- is hydrogen, on

•» j. j

the following way:

R and n are as previously stated

The compounds of formulas II and V where R 1 is hydrogen are acidic and will form salts with basic reagents. Such salts are considered to be within the scope of this invention.

These salts can be prepared by standard techniques, such as by mixing together the acidic and basic components, usually in a 1:1 molar ratio, in an aqueous, non-aqueous or semi-aqueous medium as appropriate. They are then recovered by filtration, by stripping with a non-solvent followed by filtration,

by evaporation of the solvent or, in the case of aqueous solutions, by sonication, as appropriate. Basic agents that are commonly used in salt formation belong to both organic and inorganic types, and they include ammonia, organic amines, alkali metal hydroxides, carbonates,

bicarbonates, hydrides and alkoxides, and also alkaline earth metal hydroxides, carbonates, hydrides and alkoxides. Representative examples of such bases are primary amines, so

such as n-propylamine, n-butylamine, aniline, cyclohexylamine, benzylamine and octylamine, secondary amines such as diethylamine, morpholine, pyrrolidine and piperidine, tertiary amines>such as triethylamine, N-ethylpiperidine, N-methylmorpholine and 1,5 -diazobicycloI4.3.0]non- / 5-ene, hydroxides, such as sodium hydroxide, potassium hydroxide, ammonium hydroxide and barium hydroxide, alkoxides, such as

sodium ethoxide and potassium ethoxide, hydrides, such as calcium hydride and sodium hydride, carbonates, such as potassium carbonate and sodium carbonate, bicarbonates, such as sodium bicarbonate and potassium bicarbonate, and alkali metal salts of long-chain fatty acids,

such as sodium 2-ethyl hexanoate.

Preferred salts of the compounds of formulas II and V

where R, 3 is hydrogen, are the sodium, potassium and triethylamine salts.

As previously indicated, the compounds of formulas II and V where R^^ is hydrogen or an ester-forming residue readily hydrolyzable in vivo are potent inhibitors of microbial β-lactamases, and they increase the antibacterial efficacy of β-lactam antibiotics (penicillins and cephalosporins) against many microorganisms, especially those that form a /3-lactamase. The manner in which said compounds of formulas II and V increase the effectiveness of a /J-lactara antibiotic can be assessed by

refer to experiments where MIC is measured for. a given antibiotic alone, and for a compound of formula II or V

alone. These MIC values are then compared with the MIC values obtained with a combination of a given antibiotic and the compound of formula II or V. When the antibacterial power of the combination is clearly greater than what could be expected from the powers of the individual compounds, this is considered to constitute an increase in activity. The MIC values of combinations are measured by the method described by Barry and Sabath in "Manual of Clinical Microbiology", published by Lenette, Spaulding and Truant, 2nd edition, 1974, American Society for Microbiology.

The connections with. formulas II, IV and V where R13 is hydrogen or an ester-forming residue which is easily hydrolysable in vivo, increases the antibacterial effect of β-lactam antibiotics in vivo. That is to say, they reduce the amount of antibiotics needed to protect mice against an otherwise lethal inoculation of certain /3-lact arnas e-forming bacteria.

The ability of compounds of formula II, IV or V wherein R^3 is hydrogen or an ester-forming residue readily hydrolyzable in vivo to enhance the efficacy of a β-lactam antibiotic against β-lactamase e-producing bacteria makes them valuable for co-administration with β-lactam antibiotics in the treatment of bacterial infections in mammals, especially humans. When treating a bacterial infection, said compound of formula II, IV or V can be combined with the /3-lactam antibiotic, and the two agents can thus be administered simultaneously. Alternatively, said compound of formula II, IV or V may be administered as a separate agent during the course of a treatment with a β-lactam antibiotic. In some cases it will be advantageous to administer the compound of formula II, IV or V in advance, before treatment with the β-lactam antibiotic begins.

When compounds of formula II, IV or V where R13 is hydrogen or an ester thereof which is readily hydrolyzable in vivo are used to increase the effectiveness of a β-lactam antibiotic, they are preferably administered in formulations with common pharmaceutical carriers or diluents. A pharmaceutical preparation comprising a pharmaceutically acceptable carrier, a β-lactam antibiotic and a compound of formula II, IV or V where R 3 is hydrogen or an easily hydrolyzable ester thereof, will usually contain from approx. 5 to approx. 80% by weight of the pharmaceutically acceptable carrier.

When the compounds of formula II, IV or V where R^3 is hydrogen or an ester thereof which is easily hydrolyzable in vivo, are used in combination with another β-lactam antibiotic, said compounds can be administered orally or parenterally, i.e. intramuscularly, subcutaneously or intraperitoneally. Although the attending physician will decide which dose is to be used for a human being, the ratio between the daily doses of the compounds of formula II, IV or V and the β-lactam antibiotics will usually lie in the range from approx. 1:3 to 3:1. Moreover, when using the compounds of formula II, IV or V in combination with another β-lactam antibiotic, the daily oral dose for each component will usually be in the range of about 10 to approx. 200 mg per kg body weight, and the daily parenteral dose for each component will usually be approx. 10 to approx. 400 mg per kg body weight. However, these figures are only illustrative, and in some cases it may be necessary to use doses outside these limits.

Typical β-lactam antibiotics with which the compounds of formula II, IV or V and their esters which are readily hydrolyzable in vivo can be co-administered are: 6-(2-phenylacetamido)penicillanic acid,

6-(2-phenoxyacetamido)penicillanic acid,

6-(2-phenylpropionamido)penicillanic acid

6-(D-2-amino-2-£enylacetamido)penicillanic acid,

6-(D-2-amino-2-[4-hydroxyphenyl]acetamido)penicillanic acid, 6-(D-2-amiho-2-1,4-cyclohexadienyl] acetamido-penicillanic acid, 6-(1-aminocyclohexanecarboxamido)penicillanic acid, 6-(2-Carboxy-2-phenylacetamido)penicillanic acid, 6-(2-Carboxy-2-[3-thienyl]acetamido)penicillanic acid, 6-(D-2-[4-ethylpiperazine-2,3-dione-1 -carboxamido]-2-phenylacetamido)penicillanic acid

6-(D-2-14-hydroxy-1,5-naphthyridine-3-carboxamido]-2-phenylacetamido)penicillanic acid,

6-(D-2-sulfo-2-phenylacetamido)penicillanic acid,

6-(D-2-sulfoamino-2-phenylacetamido)penicillanic acid, 6-(D-2-[imidazolidin-2-one-1-carboxamido]-2-phenylacetamido)-penicillanic acid, 6-(D-2-[3 -methylsulfonylimidazolidin-2-one-1-carboxamido]-2-phenylacetamido)penicillanic acid,

6-([Hexahydro-1H-azepin-1-yl]methyleriamino)penicillanic acid, acetoxymethyl-6-(2-phenylacetamido)penicillanate, acetoxymethyl-6-(D-2-amino-2-phenylacetamido)penicillanate, acetoxymethyl-6- (D-2-amino-2-[4-hydroxyphenyl]acetamido)-penicillanate,

pivaloyloxymethyl-6-(2-phenylacetamido)penicillanate, pivaloyloxymethyl-6-(D-2-amino-2-phenylacetamido)penicillanate, pivaloyloxymethyl-6-(D-2-amino-2-[4-hydroxyphenyl]acetamido)-penicillanate ,

1-(Ethoxycarbonyloxy)ethyl-6-(2-phenylacetamido)penicillanate, 1-(Ethoxycarbonyloxy)ethyl-6-(D-2-amino-2-phenylacetamido)penicillanate,

1-(ethoxycarbonyloxy)ethyl-6-(D-2-amino-2-[4-hydroxyphenyl]acetamido)penicillanate,

3-phthalidyl-6-(2-phenylacetamido)penicillanate,

3-phthalidyl-6-(D-2-amino-2-phenylacetamido)penicillanate, 3-phthalidyl-6-(D-2-amino-2-[4-hydroxyphenyl]acetamido)-penicillanate,

6-(2-phenoxycarbonyl-2-phenylacetamido)penicillanic acid, 6-(2-tolyloxycarbonyl-2-phenylacetamido)penicillanic acid, 6-(2-15-indanyloxycarbonyl]-2-phenylacetamido)penicillanic acid, 6-(2-phenoxycarbonyl-2-phenylacetamido)penicillanic acid -[3-thienyl]acetamido)penicillanic acid, 6-(2-tolyloxycarbonyl-2-[3-thienyl]acetamido)penicillanic acid 6-(2-[5-indanyloxycarbonyl]-2-13-thienyl]acetamido)-penicillanic acid,

6-(2,2-dimethyl-5-oxo-4-phenyl-l-imidazolidinyl)penicillanic acid, 7-(2-[2-thienyl]acetamido)cephalosporanic acid, 7-(2-[l-tetrazolyl]acetamido- 3-(2-[5-methyl-1,3,4-thiadiazolyl]-thiomethyl)-3-desacetoxymethylcephalosporanic acid,

7-(D-2-formyloxy-2-phenylacetamido)-3-(5-[1-methyltetrazolyl]-thiomethyl)-3-desacetoxymethylcephalosporanic acid, 7-(D-2-amino-2-phenylacetamido)desacetoxycephalosporanic acid, 7-alpha -methoxy-7-(2-[2-thienyl]acetamido)-3-carbamoyloxymethyl-3-desacetoxymethylcephalosporanic acid, 7-(2-cyanoacetamido)cephalosporanic acid, . 7-(D-2-hydroxy-2-phenylacetamido)-3-(5-[1-methyltetra-zolyl] thiomethyl)-3-desacetoxymethylcephalosporanic acid,

7-(D-2-amino-2-p-hydroxyphenylacetamido)desacetoxy-cephalosporanic acid, 7-(2-[4-pyridylthio]acetamido)cephalosporanic acid, 7-(D-2-amino-2[1,4-cyclohexadienyl ]acetamido)cephalosporanic acid, 7-(D-2-amino-2-phenylacetamido)cephalosporanic acid, 7-[D-(-)-alpha-(4-ethyl-2,3,-dioxo-l-piperazinecarboxamidep)-alpha- (4-hydroxyphenyl)acetamido]-3-[(1-methyl-1,2-3,4-tetrazol-5-yl)thiomethyl]-3-cephem-4-carboxylic acid, 7-(D-2-amino- 2-phenylacetamido)-3-chloro-3-cephem-4-carboxylic acid, 7-12-(2-amino-4-thiazolyl)-2-(methoxyimino)acetamido)-cephalosporanic acid,

[6R,7R-3-carbamoyloxymethyl-7(2Z)-2-methoxyimino(fur-2-yl)-acetamido-cef-3-em-4-carboxylate]

7-[2-(2-aminothiazol-4-yl)acetamido]-3-1-([1-2-dimethylaminoethyl)-1H-tetrazol-5-yl]thiomethyl]cef-3-em-4-carboxylic acid, and a pharmaceutically acceptable salt thereof..

As one skilled in the art will appreciate, some of the above β-lactam compounds are effective when administered orally or parenterally, while others are effective only when administered parenterally. When compounds of formula II, IV. or V where R^ is hydrogen or an ester thereof which is easily hydrolysable in vivo, is to be used simultaneously with (i.e. in admixture with) a β-lactam antibiotic which is only effective by parenteral administration, it will be necessary to a combination formulation suitable for parenteral use. When a compound of formula II, IV or V where R13 is hydrogen or its ester is to be used simultaneously with (combined with) a β-lactam antibiotic which is effective orally or parenterally, combinations can be formed which are suitable either for oral or parenteral administration. Moreover, it is possible to administer preparations of the compounds of formula II, IV or V orally, while at the same time a further β-lactam antibiotic is administered parenterally. It is also possible to administer preparations of the compounds of formula II, IV or V parenterally, while at the same time a further β-lactam antibiotic is administered orally.

The following examples are provided only for the purpose of further elucidating the invention. Nuclear magnetic resonance (NMR) spectra were measured at 60 MHz for solutions in deuterium chloroform (CDCl 2 ), perdeuterium dimethyl sulfoxide (DMSO-dg), or deuterium oxide (D 2 O), or are otherwise indicated, and peak positions are expressed in parts per million (ppm) precipitated from tetramethylsilane or sodium 2,2-dimethyl-2-silapentane-5-sulfonate. The following abbreviations for top-point shapes are used: s, singlet, d, doublet, t, triplet, q, quartet, m, multiplet.

Example 1

6-/ 3- Chlorpenicillanic acid

A sample of 2.95 g of sodium 6-chloro-6-iodopenicillanic acid was converted to the free acid, and was then dissolved in 125 ml of benzene under nitrogen. 1.08 ml of triethylamine was added to the solution and the mixture was cooled to 0-5°C. To the cooled mixture was then added 0.977 ml of trimethylsilyl chloride, and the reaction mixture was stirred at 0-5°C for 5 minutes, at 25°C for 60 minutes and at 50°C for 30 minutes. The reaction mixture was cooled to 25°C and the triethylamine hydrochloride was removed by filtration. The filtrate was heated to reflux and 15 mg of azobisisobutyronitrile and 2 x 02 ml of tri-n-butyltin hydride were added.

The refluxing mixture was irradiated with ultraviolet light in ;

5 minutes. The solvent was then removed by evaporation i

vacuum, and the residue was dissolved in a 1:1 mixture of tetrahydrofuran/water. The pH was adjusted to 7.0, and the tetrahydrofuran was removed by evaporation in vacuo. The aqueous phase was washed with ether, and then an equal volume of ethyl acetate was added. The pH was adjusted to 1.8 and the ethyl acetate layer was removed. The aqueous phase was extracted with additional ethyl acetate, and then the combined ethyl acetate solutions were dried and evaporated in vacuo. This gave 980 mg of 6-(3-chloropenicillanic acid).

The above product was dissolved in tetrahydrofuran and an equal volume of water was added. :pH was adjusted to 6.8 and the tetrahydrofuran was removed by evaporation in vacuo. The remaining aqueous phase was freeze-dried, and this gave 850 mg of sodium 6-(3-chloropenicillanic acid). The NMR spectrum (D 2 O) showed absorption at 5.70 (d, 1H, J = 4Hz), 5.50 (d, 1H, J = 4Hz), 4.36 (s,:1H), 1.60 (s , 3H) and 1.53 (s, 3H) ppm.

Example 2

6-/ 3- j odpenicillanic acid

The title compound was prepared by reduction of 6,6-diiodopenicillanic acid, at use of tri-n-butyltin hydride according to the method in example 1.

Example 3

6-/ 3- fluoropenicillanic acid

6- bromo- 6- fluoropenicillanic acid benzyl ester

To a solution of 7.7 ml hydrogen fluoride pyridine and 1.11 g N-bromosuccinimide in 10 ml diethyl ether cooled to -20°C was added 1.8 g 6-diazopenicillanic acid benzyl ester in 10 ml tetrahydrofuran and 5 ml diethyl ether. The reaction mixture was stirred for 15 minutes at -10°C and then poured into ice water. The organic layer was separated and the aqueous was further extracted with diethyl ether (3 x 20 mL). The organic layer and washing liquid were combined and were washed successively with a sodium bicarbonate solution and water and dried over sodium sulfate. Removal of the solvent in vacuo gave 1.6 g of impure 6-bromo-6-fluoropenicillanic acid benzyl ester.

The intermediate product was purified by chromatography on 100 g of silica gel using chloroform as eluent. Fractions of 10 ml each were collected, and the desired product was contained in fractions 30-45. Removal of chloroform gave 0.51 g of the pure intermediate.

6-/ 3- fluoropenicillanic acid benzyl ester

To a solution of 310 mg of 6-bromo-6-fluoropenicillanic acid benzyl ester ((in 15 ml of dry benzene maintained under a nitrogen atmosphere) was added 5 mg of azobisisobutyronitrile followed by 208 ml of tri-n-butyltin hydride. The mixture was irradiated with ultraviolet light for 40 minutes with external cooling to maintain the temperature at about 25° C. Removal of the solvent go 500 mg of impure product which was dissolved in 25 ml of ethyl acetate, to which 25 ml of water was then added and the pH was adjusted to 1.8 The organic phase was separated, dried over sodium sulfate and the solvent was removed in vacuo to give the desired intermediate after chromatography on silica gel.

6- ft- fluoropenicillanic acid

In a dry flask protected from moisture and air, 3.1 g of 6-/3-fluoropenicillanic acid benzyl ester are introduced into 40 ml of dry carbon tetrachloride. Two and two tenths of a gram of trimethylsilyl iodide is added and the reaction mixture is then stirred at room temperature for 1.5 hours. A saturated solution (100 ml) of sodium bicarbonate is added to the reaction mixture and the aqueous phase is separated. The separated aqueous phase is washed with diethyl ether, and an equal volume of ethyl acetate is added. The pH is adjusted to 1.8, and the organic phase is separated. The aqueous phase is further extracted with ethyl acetate (2 x 50 ml) and the ethyl acetate extracts are combined and dried over sodium sulfate. Removal of the solvent in vacuo gives the desired 6-/3-fluoropenicillanic acid.

Example 4

6- ft- methoxypenicillanic acid

6-/3-Methoxypenicillanic acid benzyl ester

Under anhydrous conditions, a mixture of 660 mg of 6-bromo-6-methoxypenicillanic acid behzyl ester (J. Am. Chem. Soc, 94,

1408 (1972), 0.468 ml of tri-n-butyltin hydride and 5 mg of azobisisobutyronitrile in 25 ml of benzene heated to reflux under a nitrogen atmosphere for 2 hours. An additional 0.05 ml of hydride was added

added, and heating was continued for a further 1 hour. The reaction mixture was concentrated to dryness under reduced pressure to give 1.05 g of the crude product.

The crude product was chromatographed over 75 g of silica gel using 2 liters of hexane. The eluent was then changed to chloroform and the chromatography continued. Fractions 68 to 102 (10 mL each) were combined and concentrated in vacuo to give 500 mg of product. The NMR spectrum (CDCl3) showed absorptions at 1.45 (s, 3H), 1.68 (s, 3H), 3.58 (s, 3H),

4.5 (s, 1H), 4.82 (d, lH, J = 4Hz) , 5.2 (s, 2H), 5.45 (d, 1H, J. = 4Hz) and 7.4 (s , 5H) ppm.

6-/ 3- methoxypenicillanic acid

A solution of 235 mg of 6-(3-methoxypenicillanic acid benzyl ester) in 15 ml of methanol was added to 235 mg of prehydrogenated palladium-on-calcium carbonate in 15 ml of water, and the resulting mixture was shaken in a hydrogen atmosphere at an initial pressure of

3.85 kg/cm 2. After 4 hours the spent catalyst was filtered off and the filtrate was concentrated. The cake was washed with methanol and water. The methanol was removed in vacuo and the combined aqueous layers were washed with ethyl acetate. The aqueous liquid was freeze-dried to give 94 mg of the desired product as the calcium salt. The NMR spectrum (D 2 O) showed absorption at 1.5 (s, 3H), 1.6 (s, 3H), 3.45 f s, 3H), 4.18 (s, 1H), 4.94 (d, 1H, J = 4Hz) and 5.45 (d, 1H, J = 4Hz) ppm.

Example 5

Using the procedure from example 4, and starting from the appropriate 6-brom-6-alkoxy ype i c i 11 ans y r e f^ e s te r ,~~~]bl e the following 6-/3-Alkoxypenicillan esters prepared: 6-^-ethoxypenicillanic acid benzyl ester, 6-Æ-methoxypenicillane acid 4-nitrobenzyl ester, 6-£-i-propoxypenicillanic acid benzhydryl ester, 6-£-n-propoxypenicillanic acid benzhydryl ester, 6-/3-n- butoxypenicillanic acid trityl ester, 6-0-methoxypenicillanic acid trityl ester, 6-0-ethoxypenicillanic acid trityl ester and 6-jS-s-, butoxypenicillanic acid 4-nitrobenzyl esters.

Starting from the above-mentioned 6-£-Alkoxypenicillanic acid ester and applying the hydrogenation process of Example 4, the following 6-/3-Alkoxypenicillanic acid calcium salts were prepared: 6-/3-Methoxypenicillanic acid, 6-j8-Ethoxypenicillanic acid, 6-£ -i£.opropoxypenicillanic acid, 6-0-n-propoxypenicillanic acid, 6-0-n-butoxypenicillanic acid, 6-/3-n-butoxypenicillanic acid and 6-/3-s-butoxypenicillanic acid.

Example 6

6- ff- methylthiopenicillanic acid

6-bromo-6-methylthiopenicillanic acid trichloroethyl ester To 4.9 g of 6,6-dibromopenicillanic acid trichloroethyl ester in 100 ml of dry tetrahydrofuran cooled to -75°C was added 5.12 ml of a 1.95 M solution of t-butyl- magnesium chloride in ether during 3-4 minutes. The reaction mixture was stirred at -75°C for 20 minutes, followed by the addition of 1.26 g of methyl methylthiosulphonate. Cold stirring was continued for just over 1 hour, followed by the addition of 1 ml of acetic acid. The reaction mixture was allowed to warm to room temperature over a period of 30 minutes. The reaction mixture was concentrated in vacuo and the residue was partitioned between water-ethyl acetate (50 ml/50 ml). The aqueous layer was further extracted with ethyl acetate (50 mL) and the combined organic extracts were washed once with

water and then with a saturated salt solution. The ethyl acetate layer was separated, dried over sodium sulfate and concentrated to a yellow oil.

The remaining oil was chromatographed over 500 g of silica gel using chloroform as eluent. Fractions 94-130, each comprising 14 ml, were combined and concentrated to give 3.0 g of the desired product as a pale yellow oil which solidified on standing, m.p. 103.5-105°C. The NMR spectrum'(CDCl-j) showed absorption at 1.55 (s, 3H), 1.7 (s, 3H), 2.4 (s, 3H), 4.6 (s, 1H), 4, 8 (s, 2H) and 5.82 (s, 1H) ppm.

6-ff- methylthiopenicillanic acid trichloroethyl ester To a solution of 500 mg of 6-bromo-6-methylthiopenicillanic acid trichloroethyl ester in 50 ml of benzene under anhydrous conditions and in a nitrogen atmosphere was added 0.29 ml of tri-n-butyltin hydride.

The resulting reaction mixture was heated at reflux for 6 hours. An additional 0.1 mL of the stannous hydride was added and heating continued overnight. The solvent was removed in vacuo to give the crude product.

The remaining material was chromatographed on 100 g of silica gel and eluted with a mixture of chloroform-ethyl acetate (95/5, vol./vol.). Fractions comprising 12 ml each were collected every half minute. Fractions 33-42 were combined and concentrated to give 300 mg of product. This was rechromatographed on 60 g silica gel, and 7 ml fractions were taken every half minute. Fractions 25-34 were combined and the solvent was removed under reduced pressure to give 190 mg of the desired product as an oil. The NMR spectrum showed absorption (CDCl 3 ) at 1.53 (s, 3H), 1.69 (s, 3H), 2.28 (s, 3H), 4.33 and 4.42 (d, 1H), 4 .54 (s, lH), 4.73 (s, 2H) and 5.48 and 5.56

(d, 1H) ppm.

6-/ 3- methylthiopenicillanic acid

In a round-bottom flask fitted with a stirrer and stopper, 1.38 g of 6-j8-methylthiopenicillanic acid trichloroethyl ester in 28 ml of tetrahydrofuran, 5.6 g of zinc dust and 5.6 ml of 1 M potassium hydrogen phosphate were brought together. The reaction mixture was allowed to stir for 15 minutes. The mixture was filtered through supergel and the cake was washed (2 x 20 mL) with tetrahydrofuran-water (50/50, vol./vol.). The washings were combined with the filtrate, and the tetrahydrofuran was removed in vacuo. The remaining oil and water were extracted (2 x -30 mL) with ethyl acetate. The ethyl acetate was removed, and the pH of the aqueous layer was adjusted to 2.5 and fresh ethyl acetate was added. The combined ethyl acetate extracts were washed with a saturated saline solution and dried over sodium sulfate. Removal of the solvent gave 620 mg of the product as a clear oil. The residue was taken up in 50 ml of ethyl acetate and treated with 490 mg of sodium 2-ethyl hexanoate in 15 ml of ethyl acetate. The precipitate formed was filtered, washed with ether and dried to give 628 mg of the desired product as its sodium salt. The NMR spectrum showed absorption (DMSO-D^) at 1.43 (s, 3H) , 1.52 (s, 3H) , 2.17 (s, 3H) , 3.86 (s, 1H) , 4, 48 and 4.55 (d, 1H) and 5.37 and 5.44 (d, 1H) ppm.

Example 7

The procedure of Example 6 was repeated starting from 6,6-dibromopenicillanic acid trichloroethyl ester and the appropriate alkyl methylthiosulfonate, and the following penicillanic acids were obtained as their sodium salts: 6-O-ethylthiopenicillanic acid, 6-/S-n-propylthiopenicillanic acid, 6- /3-i-propylthiopenicillanic acid, 6-/3-n-butylthiopenicillanic acid and 6-/3-s-butylthiopenicillanic acid.

Example 8

6-/ 3- methylthiopenicillanic acid pivaloyloxymethyl ester 6- bromo- 6- methylthiopenicillanic acid pivaloyloxymethyl ester

Under anhydrous conditions and in a nitrogen atmosphere,

4.73 g of 6,6-dibromopenicillanic acid pivaloyloxymethyl ester in 100 ml of dried tetrahydrofuran cooled to -75°C and treated with 5.12 ml of 1.95 M t-butyl magnesium chloride in ether over a period of 3-4 minutes . The resulting reaction mixture was stirred at -75°C for an additional 20 minutes, followed by the addition of 1.26 g of methyl methylthiosulfonate. After cold stirring for 15 minutes, the reaction mixture was treated with 1 ml of acetic acid and allowed to warm to room temperature. The solvents were removed in vacuo and the remaining crude product was partitioned between 50 ml of ethyl acetate and 50 ml of water. The aqueous layer was further extracted with ethyl acetate, and the organic extracts were combined, washed with a saturated saline solution and dried over sodium sulfate. The crude product, 4.6 g, was obtained by removal of the solvent under reduced pressure.

The product was purified by chromatography on 500 g of silica gel, using chloroform as eluent. Fractions containing 14 ml each were collected every 0.6 minutes. Fractions 126 to 242 were combined and concentrated in vacuo to give 2.2 g of the purified product as a pale yellow oil which crystallized on standing, m.p. 79-81°C. The NMR spectrum (CDCl3) showed absorption at 1.24 (s, 9H), 1.45 (s, 3H), 1.68 (s, 3H), 2.40 (s, 3H), 4.5 (s , 1H), 5.8 (s, 1H) and 5.88 (s, 2H) ppm.

6-ft- methylthiopenicillanic acid pivaloyloxymethyl ester

A reaction mixture of 2.2 g of 6-bromo-6-methylthiopenicillanic acid pivaloyloxymethyl ester and 2.64 ml of tri-n-butyltin hydride in 75 ml of benzene was heated under reflux under a nitrogen atmosphere and under anhydrous conditions overnight.

The solvent was removed in vacuo, and the residue was chromatographed over 400 g of silica gel using chloroform-ethyl acetate (95/-5, vol./vol.) as eluent, and fractions

... /

of 14 ral was collected every 0.6 minutes. Fractions 18-21 were combined and concentrated to give 1.6 g of product. The product was further purified by rechromatography over 350 g of silica gel, and this gave 1.2 g of the pure product as an oil. The NMR spectrum (CDCl3) showed absorption at 1.2 (s, 9H), 1.5

(s, 3H), 1.63 (s, 3H), 2.26 (s, 3H), 4.3 and 4.4 (d, 1H), 4.4

(s, IS), 5.42 and 5.5 (d, lH), and 5.61, 5.71, 5.73 and 5.83

(q, 2H) ppm.

Example 9

The procedure from Example 8 was repeated, starting from the appropriate 6,6-dibromopenicillanic acid ester and alkyl methylthiosulfate, and this gave the following congeners: 6-(3-methylthiopenicillanic acid-3-phthalidyl ester,

6-/3-Methylthiopenicillanic acid-1-(acetoxy)-ethyl ester, 6-^-Ethylthiopenicillanic acid-pivaloyloxymethyl ester, 6-/3-Ethylthiopenicillanic acid-4-crotonolactonyl ester, 6-jS-methylthiopenicillanic acid-gamma-butyroictone- 4-yl ester, 6-/3-n-propylthiopenicillanic acid acetoxymethyl ester, 6-/3-n-propylthiopenicillanic acid pivaloyloxymethyl ester, 6-/3-i-propylthiopenicillanic acid hexanoyloxymethyl ester, 6-/S-i-propylthiopenicillanic acid- l-(isobutyryloxy)ethyl ester, 6-j8-n-butylthiopenicillanic acid-l-methyl-l-(acetoxy)ethyl ester, 6-/3-n-butylthiopenicillanic acid-l-methyl-l-(hexanoyloxy)ethyl- ester, 6-Æ-s-butylthiopenicillanic acid methoxycarbonyloxymethyl ester, 6-Æ-s-butylpenicillanic acid propoxycarbonyloxymethyl ester, 6-/3-methylthiopenicillanic acid-l-(ethoxycarbonyloxy) ethyl ester, 6-0-ethylthiopenicillanic acid-l- methyl 1-(methoxycarbonyloxy)ethyl ester, and

6-(3-Methylthiopenicillanic acid 1-methyl-1-(isopropoxycarbonyl)ethyl ester).

Example 10

6-j3-jodopenicillanic acid pivaloyloxymethyl ester

6, 6-Diodepenicillanic acid pivaloyloxymethyl ester

A mixture of 5.94 g of sodium nitrite in 260 ml of water and 2.63 g of 6-(3-aminopenicillanic acid pivaloyloxymethyl ester in 260 ml of methylene chloride) was stirred while cooling in an ice bath. p-toluenesulfonic acid (1.2 g) was added in three portions over 30 minutes and the mixture was stirred for 1 hour at room temperature. The organic phase was separated and dried over sodium sulfate. Iodine (1.3 g) was added to the organic phase and the resulting solution was stirred at room temperature for 4 hours. The solution was washed with aqueous sodium thiosulfate, separated and concentrated in vacuo to a small volume. The residue was chromatographed on silica gel using petroleum ether (b.p. 60-80°C) containing an increasing proportion of ethyl acetate as eluent. The fractions containing the product were combined, dried over sodium sulfate and concentrated under vacuum to dryness to give 1.43 g, m.p. 136-138°C. The NMR spectrum (CDCl3) showed absorption at 5.79 (bs, 2H), 5.71

(s, 1H), 4.52 (s, 1H), 1.65 (s, 3H), 1.44 (s, 3H) and 1.21

(s, 9H) ppm.

6- j3- i odpenicillanic acid- pivaloyloxy methyl ester

To a solution of 1.29 g of 6,6-diiodopenicillanic acid pivaloyloxymethyl ester in 8 ml of benzene under a nitrogen atmosphere was added 500 mg of triphenyltin hydride and a few crystals (^10 mg) of azobisisobutyronitrile, and the resulting reaction mixture was heated to 50°C for 1 hour. An additional 500 mg of hydride and 10 mg of nitrile were added and heating was continued with stirring for 3 hours. Column chromatography on silica gel using petroleum ether (b.p. 60-80°C) with an increasing proportion of methylene chloride as eluent gave 140 mg of the desired product, m.p. 73-77°C. The NMR spectrum (CDCl 3 ) showed absorption at

5.9 (d, AB, J 5.8Hz), 5.82 (d, AB, J = 5.8Hz), 5.66 (d, lH, AB, J = -4.1Hz), 5.42 (d, 1H, AB, J = 4.1Hz), 4.59 (s, 1H), 1.71

(s, 3H)', 1.50 (s, 3H) and 1.24 (s, 9H) ppm.

Example 11

6-/ 3- 1 odpenicillanic acid benzyl ester

In a similar manner to Example 10, 6-O-aminopenicillanic acid benzyl ester was converted to 6,6-diiodopenicillanic acid benzyl ester. The NMR spectrum (CDCl 3 ) showed absorption at 7.40 (m, 5H), 5.77 (s, 1H), 5.21 (s, 2H), 4.59 (s, 1H), 1.67 (s , 3H) and 1.37 (s, 3H) ppm.

The isolated 6,6-diiodopenicillanic acid benzyl ester was converted to 6-(3-iodopenicillanic acid benzyl ester using the appropriate part of the procedure in Example 10. The NMR spectrum |( CDCl^~)| showed absorption at 7.42 (ra, 5H), 5.64 (d, 1H, AB, J = 4.0 Hz), 5.42 (d, 1H, AB, J = 4.0 Hz), 4, 59 (s, 1H), 1.69 (s, 3H) and

1.40 (s, 3H) ppm.

Example 12

By starting from the appropriate 6-/3-aminopenicillanic acid ester

and using the procedure from Example 10, the following 6-/3-iodopenicillanic acid esters were prepared:

6-/3-Iodopenicillanic acid-3-phthalidyl ester, 6-/3-Iodopenicillanic acid-1-(acetoxy) ethyl ester, 6-/3-Iodopenicillanic acid-4-crotonolactonyl ester, 6-/3-j odpenicillanic acid T -butyrolacton-4-yl ester, 6-/3-iodopenicillanic acid acetoxymethyl ester, 6-/3-Iodopenicillanic acid hexanoyloxymethyl ester, 6-/3-Iodopenicillanic acid 1-(isobutyryloxy) ethyl ester, . 6-/3-Iodopenicillanic acid methoxycarbonyloxymethyl ester, 6-/3-Iodopenicillanic acid propoxycarbonyloxymethyl ester, 6-/3-Iodopenicillanic acid 1-(ethoxycarbonyloxy) ethyl ester, 6-/3-Iodopenicillanic acid-1- (butoxycarbonyl) ethyl ester, . 6-(3-iodopenicillanic acid-1-methyl-1-(methoxycarbonyloxy)ethyl ester, and 6-(3-iodopenicillanic acid)-1-raethyl-1-(isopropoxycarbonyl)ethyl ester.

Example 13

6- <3- Chlorpenicillanic acid- acetox methyl ester

6- chloro- 6- iodopenicillanic acid- acetoxy methyl ester

To a solution of 5.03 g of 6-chloro-6-iodopenicillanic acid in 50 ml of acetone and 50 ml of acetonitrile is added 900 mg of diisopropylethylamine followed by 0.7 ml of acetoxyethyl bromide. The resulting solution is stirred at room temperature for 48 hours. A further 0.7 ml of bromide and 900 mg of amine are added and stirring is continued for a further 48 hours. The solution is concentrated in vacuo to dryness and the residue is suspended in ethyl acetate. The insoluble matter is filtered off and the filtrate is washed successively with water, in N hydrochloric acid and saturated aqueous sodium bicarbonate solution. The organic phase is dried, and the solvent is removed under vacuum. The remaining product is chromatographed on silica gel using methylene chloride as eluent. The fractions containing the desired material are combined, and the solvent is removed under vacuum.

6- fichlorpenicillansvre- acetoxy ethyl ester

A solution of 833 mg of 6-chloro-6-iodopenicillanic acid acetoxymethyl ester and 700 mg of diphenylmethyltin hydride in 20 ml of toluene is heated to 80°C under a nitrogen atmosphere for 4.5 hours. The solvent is removed in vacuo, and the residue is chromatographed on silica gel using methylene chloride as eluent. Fractions containing the product were combined and concentrated to dryness to give 6-(3-chloropenicillanic acid acetoxymethyl ester).

Example 14

Using the method from example 13, and starting from the required halide, the following 6-/3-chloropenicillanic acid esters were prepared: 6-/3-chloropenicillanic acid-3-phthalidyl ester,

6-(3-chloropenicillanic acid 1-methyl-1-(isopropoxy) ethyl ester,

6-/S-chloropenicillanic acid pivaloyloxymethyl ester,

6-j8-chloropenicillanic acid-4-crotonolactonyl ester,

6-j3-Chloropenicillanic acid 1-methyl-1-(methoxycarbonyloxy) ethyl ester, 6-/3-Chloropenicillanic acid V-butyrolactonyl-4-yl ester, 6-/3-Chloropenicillanic acid hexanoyloxymethyl ester,

6-/3-Chloropenicillanic acid 1-(butoxycarbonyloxy) ethyl ester, 6-/3-Chloropenicillanic acid 1-(isobutyryloxy) ethyl ester, 6-/?-Chloropenicillanic acid methoxycarbonyloxymethyl ester, and 6-/5-Chloropenicillanic acid -propoxycarbonyloxymethyl ester.

Example 15

6-/ 3- fluoropenicillanic acid- 1-( ethoxycarbonyloxy) ethyl ester 6-bromo- 6- fluoropenicillanic acid- 1-( ethoxycarbonyloxy) ethyl ester 6-diazopenicillanic acid- 1-(ethoxycarbonyloxy) ethyl ester

(3.7 g) in 20 ml of tetrahydrofuran and 10 ml of diethyl ether is added to a solution of 15.4 ml of hydrogen fluoride-pyridine and 2.22 g of N-bromosuccinimide in 20 ml of diethyl ether cooled to -20 C. The reaction mixture is stirred at - 10°C for 20 minutes, and then quench in ice water. The organic phase is separated, and the aqueous layer is further extracted with diethyl ether (3 x 40 ml). The organic phase and extracts are combined, washed successively with an aqueous sodium bicarbonate solution and water, and dried over sodium sulfate. Removal of the solvent under reduced pressure

gives the crude 6-bromo-6-fluoropenicillanic acid 1-(ethoxycarbonyloxy)ethyl ester.

The intermediate product is purified by chromatography on 200 g of silica gel using chloroform as eluent. The fractions containing the desired compounds are combined and the solvent is removed in vacuo.

6-/3-fluoropenicillanic acid-1-(ethoxycarbonyloxy) ethyl ester To a solution of 614 mg of 6-bromo-6-fluoropenicillanic acid-1-tethoxycarbonyloxy) ethyl ester in 15 ml of dry toluene under a nitrogen atmosphere is added 7 mg of azobisisobutyronitrile followed by 500 ml of di- n-butylphenyltin hydride. The reaction mixture is irradiated with ultraviolet light for 70 minutes under external cooling to keep the temperature at approx. 25°C. The solvent is removed in vacuo, and the residue is treated with 50 ml of water. The pH of the mixture is adjusted to 1.8, and the organic phase is separated, dried over sodium sulfate and concentrated to dryness, and this gives the desired product, which can be further purified by chromatography.

Example 16

Starting from the necessary 6-diazopenicillanic acid ester and applying the method from example 15, the following compounds are prepared: 6-/3-fluoropenicillanic acid methoxycarbonyloxymethyl ester, 6-/3-fluoropenicillanic acid pivaloyloxymethyl ester,

6-(3-fluoropenicillanic acid 3-phthalidyl ester,

6-/3-Fluoropenicillanic acid-1-methyl-1-(isopropoxy) ethyl ester, 6-/3-Fluoropenicillanic acid-4-crotonolactonyl ester,

6-/3-Fluoropenicillanic acid 1-methyl-1-(methoxycarbonyloxy) ethyl ester, 6-/3-Fluoropenicillanic acid- "^-butyrolactonyl-4-yl ester, 6-/3-Fluoropenicillanic acid hexanoyloxymethyl ester, 6-/3-fluoropenicillanic acid 1-butoxycarbonyloxy>ethyl ester, 6-/3-fluoropenicillanic acid 1-(isobutyryloxy)ethyl ester, 6-/3-fluoropenicillanic acid propoxycarbonyloxymethyl ester, and 6-jS-fluoropenicillanic acid- acetoxymethyl ester.

Example 17

6-/ 3-Methoxypenicillanic acid pivaloyloxy methyl ester 6- bromo- 6- methoxypenicillanic acid pivaloyloxymethyl ester A mixture of 11.88 g of sodium nitrite in 500 ml of water and 5.26 g of 6-Æ-aminopenicillanic acid pivaloyloxymethyl ester in 500 ml of methylene chloride is stirred while cooling in a ice bath. p-toluenesulfonic acid (2.4 g) is added in 3 equal portions over the course of 30 minutes, and the mixture is stirred for 1 hour at room temperature. The organic phase is separated and dried over sodium sulfate. A solution of 2.21 g of N-bromoacetamide in 100 ml of absolute methanol is added over a period of 10 minutes to the organic phase at -10°C, and the resulting reaction solution is stirred at 0°C for 2 hours. The solution is washed with saturated salt solution, and the organic phase is separated, dried over sodium sulphate and concentrated under reduced pressure. The residue is chromatographed on silica gel using benzene containing increasing amounts of ethyl acetate as eluent. The fractions containing the desired intermediate are combined and concentrated in vacuo to dryness.

6- fimethoxypenicillanBvre- pivaloyloxymethyl ester

To a solution of 1.93 g of 6-bromo-6-methoxypenicillanic acid pivaloyloxymethyl ester in 20 ml of dry toluene under a nitrogen atmosphere is added 1 g of dibenzylethyltin hydride and a few crystals of azobisisobutyronitrile, and the resulting reaction mixture is heated to 50°C for 1 hour . A further 750 mg of hydride and 10 mg of nitrile are added, and stirring is continued at 50° C. for a further 3 hours. Column chromatography on silica gel. when using cyclohexane with increasing proportions of ethyl acetate as eluent is used to purify the desired product. The fractions containing product are combined and concentrated in vacuo to dryness.

Example 18

Using the method from example 17, and starting from the appropriate 6-/3-aminopenicillanic acid ester and the necessary alcohol, the following compounds are prepared: 6-/3-methoxypenicillanic acid-3-phthalidyl ester,

6-(3-Ethoxypenicillanic acid 1-(acetoxy) ethyl ester).

6-/3-Methoxypenicillanic acid acetoxymethyl ester,

6-/3-isopropoxypenicillanic acid 4-crotonolactonyl ester, 6-O-n-butoxypenicillanic acid "V-butyrolactone-4-y.l-ester, 6-/3-n-propoxypenicillanic acid hexanoyloxymethyl ester, 6-Æ-methoxypenicillanic acid -hexanoyloxymethyl ester, 6-/3-s-butoxypenicillanic acid-raethoxycarbonyloxyethyl ester,

6-j3-ethoxypenicillanic acid ethoxycarbonyloxymethyl ester, 6-β-n-butoxypenicillanic acid 1-(ethoxycarbonyloxy)ethyl ester,

6-/3-n-propoxypenicillanic acid 1-(butoxycarbonyl)ethyl ester, 6-/3-methoxypenicillanic acid 1-methyl-1-(methoxycarbonyloxy)ethyl ester, and

6-/3-n-butoxypenicillanic acid-1-methyl-1-(isopropoxycarbonyloxy) -

ethyl ester.

Example 19

6-/ 3- Chlorpenicillanic acid-^ sulphoxide- sodium salt

A solution containing 100 mg of 6-(3-chloropenicillanic acid sodium salt) and 83 mg of sodium meta-periodate in 5 ml of water was stirred at room temperature for 90 minutes. Ethyl acetate was added, and the pH of the aqueous liquid was adjusted to 1.8 with 6N hydrochloric acid. The organic phase was separated and the aqueous layer was further extracted with ethyl acetate (3 x 10 ml). The organic phase and washings were combined, washed in ijbake with water and a saturated salt solution and dried over sodium sulfate. The solvent was removed in vacuo, and the residue with free acid was dissolved in tetrahydrofuran. An equal volume of water was added and the pH of the resulting solution was adjusted to 6.8 with dilute sodium hydroxide solution. The tetrahydrofuran was removed in vacuo and the remaining aqueous solution was freeze-dried to provide 45 mg of the sodium salt of the desired product. The NMR spectrum (acetone-D^) of the free acid showed absorption at 5.6 and 5.7 (2 sets of doublets, 1H (3:1), J = 4Hz), 4.92 and 5.3

(2 sets of doublets, 1H, (3:1), J = 4Hz), 4.56 (s, 3H), 1.7 (s, 3H) and 1.3 and 1.36 (2 singlets (3:1 ), 3H) ppm.

Example 20

6-/ 3- chlorpenicillanic acid sulfone sodium salt

A solution of 185 mg of

potassium permanganate and 0.063 ml of 85% phosphoric acid in 5 ml of water.

The pH was maintained between 6.0 and 6.5 by careful addition of dilute sodium hydroxide solution. When the permanganate color becomes persistent, the dropwise addition is stopped. A small amount of sodium bisulphite was added to get rid of the permanganate color. The reaction mixture was passed through supergel and 25 ml of ethyl acetate was added to the filtrate. The pH was adjusted to 1.8 with 6N hydrochloric acid, and the organic phase was separated. The aqueous phase was further extracted with ethyl acetate (3. x 10 ml). The organic phase and washings were combined, backwashed with water and a saturated salt solution and dried over sodium sulfate. Removal of the solvent in vacuo gave 118 mg of the desired acid.

The acid was dissolved in tetrahydrofuran, to which it was added

an equal volume of water. The pH was adjusted to 6.8 with a dilute sodium hydroxide solution. The tetrahydrofuran was removed in vacuo and the residue was freeze-dried to give 90 mg of the sodium salt of the desired product. The NMR spectrum (acetone-D^) of the free acid showed absorption at 5.82 (d, 1H, J 4Hz), 5.25 (d, 1H,

J = 4Hz), 4.54 (s, 1H), 1.65 (s, 3H) and 1.5 (s, 3H) ppm.

Example 21

6- ft- chlorpenicillanic acid- sulfone

6- chloro- 6- iodopenicillan- sulfone

To a suspension of 3.0 g of 6-chloro-6-iodopenicillanic acid in a mixture of 25 ml of methylene chloride and 15 ml of water was added sufficient 3N sodium hydroxide solution to achieve a pH of 7.0. The aqueous phase was separated, and the organic layer was extracted several times with water. The aqueous phase and washings were combined, cooled to 5°C, and treated dropwise over a period of 20 minutes with a solution which re- . contained 1.64 g of potassium permanganate and 0.8 ml of phosphoric acid in 25 ml of water. The temperature was kept at 5-8°C and the pH at 5.5-6.0 by adding 3N sodium hydroxide solution.

Ethyl acetate (30 mL) was added to the reaction mixture, and the pH was adjusted to 1.5 with 6N hydrochloric acid. A 10% solution of sodium bisulfite (20 ml) was added dropwise, and the pH was kept below 1.6 with 6N hydrochloric acid. The layers were separated and the aqueous was further extracted with ethyl acetate. The combined ethyl acetate layers and washings were dried over sodium sulfate and concentrated in vacuo to give 2.4 g of the desired intermediate, m.p. 137-139°C.

6- jS- chlorpenicillanic acid- sulfone

To a solution of 3.02 g of 6-chloro-6-iodopenicillanic acid sulfone in 125 ml of toluene at 0-5°C was added, under a nitrogen atmosphere, 1.08 ml of triethylamine followed by 0.977 ml of trimethylsilyl chloride. After stirring for 5 minutes at 0-5°C, 60 minutes at 25°C and 30 minutes at 50°C, the reaction mixture was cooled to

25°C, and the triethylamine hydrochloride was removed by filtration. To the resulting filtrate was added 15 mg of azobisisobutyronitrile, followed by 2.02 ml of tribenzyltin hydride. The mixture was irradiated with ultraviolet light for 15 minutes with external cooling to maintain the temperature at approx. 20-25°C. The solvent was removed in vacuo, and the residue was dissolved in a 1:1 mixture of tetrahydrofuran - water. The pH was adjusted to 7.0 and the tetrahydrofuran was removed under reduced pressure. The remaining aqueous solution was extracted with diethyl ether followed by the addition of an equal volume of ethyl acetate. The pH was adjusted to 1.8 with 6N hydrochloric acid, and the organic phase was separated. The aqueous liquid was further extracted with ethyl acetate, and the combined organic layers and washings were concentrated under vacuum to dryness to give the desired product, identical to that of Example 20.

Example 22

Starting from a suitable penicillanic acid and applying the procedure in the given example, the following compounds were prepared:

Example 23

Pivaloyloxymethyl- 6-ft-bromopenicillanate

To a solution of 280 mg of 6-/8-bromopenicillanic acid in 2 ml of N,N-dimethylformamide was added 260 mg of diisopropylethylamine followed by 155 mg of chloromethyl pivalate and 15 mg of sodium iodide. The reaction mixture was stirred at room temperature for 24 hours, and was then diluted with ethyl acetate and water. pH was adjusted to 7.5,

and then the ethyl acetate layer was separated and washed three times with water and once with saturated sodium chloride solution. The ethyl acetate solution was then dried using anhydrous sodium sulfate and evaporated in vacuo to give the title compound.

Example 24

Reaction of the appropriate 6-halogenopenicillanic acid with 3-phthalidyl chloride, 4-crotonolactonyl chloride, gamma-butyrolacton-4-yl chloride or the required alkanoyloxymethyl chloride, 1-(alkanoyloxy)ethyl chloride, 1-methyl-1-(alkanoyloxy)ethyl chloride, alkoxycarbonyloxymethyl- chloride, 1-(Alkoxycarbonyloxy)ethyl chloride or 1-methyl-1-(Alkoxycarbonyloxy)ethyl chloride, according to the procedure in Example 23, gives the following compounds: 3-phthalidyl-6-(3-chloropenicillanate, 3-phthalidyl-6 -/3-fluoropenicillanate, 3-phthalidyl-6-/3-methoxypenicillanate, 4-crotonolactonyl-6-/3-bromopenicillanate, 4-crotonolactonyl-6-Æ-iodopenicillanate, 4-crotonolactonyl-6-Æ-ethylthiopehicillanate, ~ Y -butyrolacton-4-yl-6-i3-bromopenicillanate , T -butyrolacton-4-yl-6-|3-fluoropenicillanate , T -butyrolacton-4-yl-6-0-ethoxypenicillanate , acetoxyethyl 6-(/3-bromopenicillanate , pivaloyloxymethyl-6-/3-methyl thiopenicillanate, hexanoyloxymethyl-6-/3-methylthiopenicillanate, 1-(acetoxy)ethyl-6-/3-n-propoxypenicillanate, 1-(isobutyryloxy)ethyl-6-/3- chloro-penicillanate, 1-methyl-1-(hexanoyloxy)ethyl-6-Ø-methylthio-penicillanate, methoxycarbonyloxymethyl-6-/3-bromopenicillanate, n-propoxycarbonyloxymethyl-6-/J-methoxypenicillanate, 1-(ethoxycarbonyloxy)ethyl- 6-? methoxycarbonyloxy)ethyl-6-O-fluoropenicillanate, respectively.

Example 25

6- bromopenicillanic acid pivaloyloxy methyl ester sulfone 6, 6- dibromopenicillanic acid pivaloyloxy methyl ester sulfone

To a solution of 1.8 g of 6,6-dibrorapenicillanic acid pivaloyloxymethyl ester in 50 ml of chloroform was added 1.63 g of 80% m-chloroperbenzoic acid, and the resulting reaction mixture was stirred at room temperature overnight. Water (30 mL) was added and sufficient sodium bisulfite was added to give a negative starch-iodine-paper test. The pH was adjusted to 7.5 with dilute sodium hydroxide solution and the organic phase was separated. The aqueous liquid was further extracted with chloroform, and the organic phase and washings were combined, dried over sodium sulfate and concentrated to dryness. The residue was chromatographed on 250 g of silica gel using chloroform as eluent. The fractions containing the product were combined and concentrated to give 1.2 g of the desired compound.

• 6-^- bromopenicillansvre- pivalovloxymethylester- sulfone

500 mg of triphenyltin hydride and a few crystals of azobisisobutyronitrile were added to a solution of 1.15 g of 6,6-dibromopenicillanic acid-pivaloyloxymethyl ester-sulphurH(I)/10 ml of toluene under a nitrogen atmosphere. The resulting reaction mixture was heated to 40°C for 30 minutes. An additional 250 mg of hydride and a small amount of nitrile were added and heating was continued for another 30 minutes. The solvent was removed in vacuo and the residue was treated with 150 ml of chloroform. The mixture was filtered and the filtrate chromatographed on silica gel using chloroform with increasing proportions of ethyl acetate as eluent. The fractions containing the product were combined and concentrated in vacuo to give the desired compound.

Example 26

6-/ 3- chloropenicillanic acid acetoxymethyl ester sulfoxide 6- chloro- 6-iodopenicillanic acid acetoxymethyl ester sulfoxide To a solution of 2.1 g of 6-chloro-6-iodopenicillanic acid acetoxymethyl ester in 55 ml of chloroform was added 1, 06 g with 80% m-chloroperbenzoic acid, and the resulting reaction mixture was stirred at room temperature overnight. Water (35 mL) was added, and excess peracid was destroyed by careful addition of sodium bisulfite solution using starch-iodine paper as an indicator. The pH of the aqueous liquor was adjusted to 7.5

and the aqueous liquid was separated. The aqueous liquid was

extracted (2 x 10 mL) with chloroform and then discarded. The original chloroform layer and washings were combined, washed with a saturated saline solution and dried over sodium sulfate. The residue was, after removal of the solvent in vacuo, dissolved in 60 ml of chloroform and chromatographed on 250 g of silica gel using chloroform as eluent. The fractions containing the product were combined, and the solvent was removed under reduced pressure.

6-/3-Chloropenicillanic acid-acetoxymethyl-ester-sulphoxide Under anhydrous conditions and under a nitrogen atmosphere, 2.63 ml of tri-n-butyltin hydride was added to a solution of 4.35 g of 6-chloro-6-iodo-penicillanic acid-acetoxymethyl ester -sulfoxide in 150 ml of dry toluene, and the resulting reaction mixture was stirred at 80°C for 20 minutes. Water (50 mL) was added to the reaction mixture and the organic phase was separated. The organic

phase was concentrated in vacuo, and the residue was dissolved in 75 ml of chloroform. The resulting solution was chromatographed on 200 g of silica gel using chloroform as eluent. The fractions containing the desired product were combined and evaporated to dryness in vacuo.

Example 27

.Starting from a suitable 6,6-disubstituted penicillanic acid ester and applying the indicated method, the following was

compounds synthesized:

Example 28

6- phiraethylthiopenicillansvre- pivaloyloxyethyl- ester- sulfone

6-bromo-6-methylthiopenicillanic acid pivaloyloxyethyl ester sulfone

To 12.37 g of 6,6-dibromopenicillanic acid pivaloyloxymethyl ester sulfone in 175 ml of tetrahydrofuran contained in a flask fitted with a stirrer, cold temperature thermometer and nitrogen inlet, and cooled to -75°C, was added 9.4 ml of a 2.6 M solution

of t-butyl magnesium chloride in tetrahydrofuran over a period of 5 min. The reaction mixture was stirred for 20 minutes at -75°C and then treated with 3.09 g of methyl methylthiosulfonate. Stirring was continued for 3 hours at -75°C,

1 hour at -50°C and 2 hours at 0°C. Acetic acid (3.5 ral) was added to the reaction mixture and the resulting solution was stirred for 15 minutes. The reaction mixture was then concentrated in vacuo and the residue was partitioned between water-ethyl acetate (50 ml/50 ml). The aqueous layer was further extracted with ethyl acetate

(50 mL), and the combined organic extracts were washed once with water and then with saturated saline. The ethyl acetate layer was separated, dried over sodium sulfate and concentrated to give the crude product.

The remaining oil was chromatographed on 500 g of silica gel using chloroform as eluent. The fractions containing the product were combined and concentrated to give the desired material.

■3"

6-/ 3- methylthiopenicillanic acid pivaloyloxymethyl ester sulfone Under one nitrogen atmosphere and anhydrous conditions, a solution of 1.45 g of 6-bromo-6-methylthiopenicillanic acid pivaloyloxymethyl ester sulfone and 0.81 ml of tri-n- butyl tin hydride in 50 ml t<p>luen heated at 50°C for 3 hours. The toluene was removed in vacuo and the residue was treated with .25 ml of ethyl acetate. The desired product crystallized on standing in the cold overnight.

Example 29

Using the method from Example 28, and starting from the appropriate penicillanic acid ester sulfone or sulfoxide and the necessary alkyl methyl thiosulfonate, the following compounds were prepared: 6-Æ-methylthiopenicillanic acid-3-phthalidyl ester sulfoxide, 6-O-α-ethylthiopenicillanic acid -l-(acetoxy)ethyl ester sulfone, 6-/3-ethylthiopenicillanic acid pivaloyloxymethyl ester sulfone, 6-/S-ethylthiopenicillanic acid-4-crotonolactonyl ester sulfoxide, 6-/3-methylthiopenicillanic acid- T - butyrolacton-4-yl-ester-sulfone, 6-/3-n-propylthiopenicillanic acid-acetoxymethyl-ester-sulfoxide, 6-£-i-propylthiopenicillanic acid-hexanoyloxymethyl-ester-sulfone, e-/3-i-propylthiopenicillanic acid-l - (isobutyryloxy) ethyl ester- sulf oxide,.

6-/3.-n-Butylthiopenicillanic acid-1-methyl-1-(acetoxy) ethyl ester sulfoxide,

6-/3-n-Butylthiopenicillanic acid-1-methyl-1-(hexanoyloxymethyl) ethyl ester sulfone,

6-/3-s-Butylthiopenicillanic acid-methoxycarbonyloxy-methyl-ester-sulfone,

6-/S-s-butylthiopenicillanic acid propoxycarbonyloxymethyl ester sulfoxide,

6-(3-methylthiopenicillanic acid-1-(ethoxycarbonyloxy)ethyl ester sulfoxide,

6-β-ethylthiopenicillanic acid-1-methyl-1-(methoxycarbonyloxy)ethyl ester sulfone, and

6-N-methylthiopenicillanic acid-1-methyl-1-(isopropoxycarbonyloxy)-ethyl ester sulfoxide.

Example 30

6-ft-bromopenicillans acid-1-(ethoxycarbonyloxy) ethyl ester sulfone

6,6-Dibromopenicillanic acid-1-(ethoxycarbonyloxy)ethyl ester sulfone

Under a nitrogen atmosphere, 240 mg of lithium hydroxide was added to 3.91 g of 6,6-dibromopenicillanic acid sulfone in 30 ml of dimethyl sulfoxide, and the resulting solution was stirred at room temperature for 2 hours. Then, 810 mg of tetrabutylammonium bromide, 0.56 ml of N-methylmorpholine, and 3.64 g of α-chlorodiethyl carbonate were added to the reaction mixture in the indicated order, and the reaction mixture was stirred at room temperature overnight.

The reaction mixture was poured into 50 ml of 0.1N hydrochloric acid and washed with diethyl ether. Removal of the ether gave 2.98 g of the crude product as a brown oil. A 500 mg sample was chromatographed on silica gel using ethyl acetate-hexane (1:2, vol./vol.) as eluent to give a 210 mg sample of the pure product.

6-(3-Bromopenicillanic acid-1-(ethoxycarbonyloxy) ethyl ester sulfone).

To a solution of 2.53 g of 6,6-dibromopenicillanic acid-1-(ethoxycarbonyloxy)ethyl ester sulfone in 125 ml of dry toluene cooled to -5°C was added 1.82 g of diphenylbenzyltin hydride followed by 10 mg of azobisisobutyronitrile. The resulting solution was irradiated with ultraviolet light for 20 minutes with external cooling to maintain the temperature at 25°C. The solvent was removed in vacuo, and the residue was dissolved in a 1:1 mixture of ethyl acetate/water and the pH was adjusted to 6.8. The ethyl acetate was separated, and the aqueous phase was further extracted with fresh ethyl acetate. The organic phase and washings were combined, washed with water and a saturated saline solution and dried over sodium sulfate. Removal of the solvent under reduced pressure gave the desired product.

Example 31

Starting from a suitable 6,6-disubstituted penicillane ester sulfone or sulfoxide, and applying the procedure of Example 30, the following compounds were prepared: 6-(3-fluoropenicillanic acid-3-phthalidyl ester) -sulf oxide, 6-/3-fluoropenicillanic acid-4-crotonolactonyl ester sulfoxide, 6-/3-fluoropenicillanic acid-1-methyl-1-(methoxycarbonyloxy)ethyl ester-sulfone, 6-^-fluoropenicillanic acid-1-( butoxycarbonyloxy)ethyl sulfone, 6-/3-Fluoropenicillanic acid~ Y-butyrolacton-4-yl-ester-rsulfoxide, 6-/3-Chloropenicillanic acid-3-phthalidyl-ester-sulfoxide, 6-/3-Chloropenicillanic acid-methoxycarbonyloxymethyl-ester-sulfoxide, 6-/3- /3-Chloropenicillanic acid-crotonolactonyl-ester-sulfone, 6-/3-Chloropenicillanic acid-1-(propoxycarbonyloxy)ethyl-ester-sulfoxide, e-Ø-chloro<p>enicillans<y>re-l-^met< y>l-l-dso<p>ro<p>ox<y>carbon<y>lox<y>) ethyl-ester-sulfoxide, 6-/3-chloropenicillanic acid-ethoxycarbonyloxyacid ethyl-ester-sulfony 6-/3-bromopenicillanic acid -l-methyl-l-(propoxy-carbonyloxy) ethyl ester sulfone, 6-/3-bromopenicillanic acid methoxycarbonyloxymethyl ester sulfoxide, 6-/3-bromopenicillanic acid-l- (butoxycarbonyloxy) ethyl ester sulfoxide, 6-0-bromopenicillan-^acid-3-phthalidyl ester sulfoxide, 6-/3-bromopenicillanic acid-T-butyrolacton-4-yl-ester-sulfone, 6-£- iodopenicillanic acid 3-phthalidyl ester sulfoxide, 6-/3-iodopenicillanic acid 4-crotonolactonyl ester sulfone, 6-0-iodopenicillanic acid methoxycarbonyloxymethyl ester sulfoxide, 6-/3-iodopenicillanic acid propoxycarbonyloxymethyl ester sulfoxide, 6-/3-iodpenicillanic acid-1-(butoxycarbonyloxy)ethyl ester sulfone, 6-/3-iodpenicillanic acid-1-methyl-1-(isopropoxycarbonyloxy)ethyl ester sulfoxide, 6-^-methoxy- Pehicillanic acid methoxycarbonyloxymethyl ester sulfoxide, 6-/3-Methoxypenicillanic acid 1-(ethoxycarbonyloxy)ethyl ester sulfoxide, 6-£-Methoxypenicillanic acid 1-methyl-1-(isopropoxycarbonyloxy)ethyl ester sulfoxide, 6 -/3-ethoxypenicillanic acid- Y -butyrolactone-*-4-yl-ester sulfone, 6-/3-ethoxypenicillanic acid-3-phthalidyl ester sulfoxide, 6-/3-n-propoxypenicillanic acid-1-(propoxycarbonyloxy) - ethyl ester sulfoxide, 6-/3-i-propoxypenicillanic acid-1-methyl -1-(methoxycarbonyl) ethyl ester sulfone, 6-/3-n-butoxypenicillanic acid-3-phthalidyl ester sulfone, 6-/3-s-butoxypenicillanic acid ethoxy-carbonyloxymethyl ester sulfone, 6-/3-n-butoxypenicillanic acid- "V-crotonolactonyl ester sulfone, 6-/3-n-butoxypenicillane-1-methyl-1-(butoxycarbonyloxy) ethyl ester sulfoxide, and 6-/3-n-butoxypenicillanic acid-1-methyl-1- (i-Propoxycarbonyloxy)ethyl ester sulfoxide.

Example 32

6-/ 3- bromopenicillansvre

A mixture of 5.0 g of 6,6-dibromopenicillanic acid, 1.54 ml of triethylamine and 100 ml of benzene was stirred under nitrogen until a solution was obtained. The solution was cooled to 0-5°C for 2-3 minutes, and 1.78 ml of trimethylsilyl chloride was added. The reaction mixture was stirred at 0-5°C for 2-3 minutes, and then at 50°C for 35 minutes. The cooled reaction mixture was filtered and the filtrate was cooled to 0-5°C. A small amount of azobisisobutyronitrile was added, followed by 3.68 mL of tri-n-butyltin hydride. The reaction flask was irradiated with ultraviolet light for 15 minutes, and then it was stirred at approx. 25°C for 1.75 hours. The reaction mixture was irradiated again for 15 minutes, and then stirring was continued for 2.5 hours. At this point one became further

small amount of azobisisobutyronitrile added, followed by 0.6 ml

tri-n-butyltin hydride, and the mixture was again irradiated for 30

minutes. The solvent was then removed by evaporation in vacuo, and to the residue was added 5% sodium bicarbonate solution and diethyl ether. The two-phase system was shaken vigorously for 10 minutes and then the pH was adjusted to 2.0. The ether layer was removed, dried and evaporated in vacuo to give 2.33 g of an oil. The oil was converted to a sodium salt with sodium bicarbonate followed by freeze-drying of the solution thus obtained. This gave sodium 6-Æ-bromopenicillanic acid, contaminated with a small amount of the alpha isomer.

The sodium salt was purified by chromatography on Sephadex LH-20. The NMR spectrum (D 2 O) of the product thus obtained showed absorptions at 5.56 (s, 2H), 4.25 (s, 1H), 1.60 (s, 3H) and 1.50 (s, 3H) ppm .

Example 33

6-fibromopenicillanic acid

To 4000 ml of dry toluene was added 1000 g of 6,6-dibromopenicillanic acid and 390 ml of triethylamine, and the resulting slurry was slowly cooled to 20-25°C. Trimethylchlorosilane (355 ml) was added dropwise over a period of 10 minutes and the reaction mixture was allowed to warm to 25°C. The triethylamine hydrochloride was filtered and the solid was washed with 1.75 liters of toluene. To the combined original filtrate and washings in a flask under a nitrogen atmosphere was added 733 mL of tri-n-butyltin hydride in 1000 mL of toluene at a rate of 18-20 mL/minute. When the addition was complete, the reaction mixture was stirred for one hour and then quenched in 7 liters of a saturated sodium bicarbonate solution. The layers were separated and the organic layer was further extracted with an additional 3 liters of the saturated sodium bicarbonate solution. The aqueous layer and extracts were combined, treated with 5 liters of ethyl acetate and treated with sufficient 12N hydrochloric acid to bring the pH to 1.55. The ethyl acetate layer was separated, and the aqueous was further extracted with 2.5 liters of ethyl acetate. The original layer and extracts were combined, dried

over sodium sulfate and treated with 2.26 liters of an ethyl acetate solution containing an equivalent amount of sodium 2-ethyl hexanoate. The precipitated sodium salt was kept at 8-10°C overnight and then filtered and dried to give 391.5 g of crystalline material.

The above-mentioned sodium salt (380 g) was dissolved in 1.9 liters of deionized water at 8°C, and was then treated with sufficient

6N hydrochloric acid to give a pH of 1.5. After stirring for 1 hour in the cold (3-5°C), the precipitated free acid was filtered and washed with 500 ml of cold water. 100 ml of water was added to the water-wet free acid in 2 liters of ethyl acetate at 8°C, and the pH was adjusted to 1.5 with 6N hydrochloric acid. The organic layer was separated and the aqueous was extracted with additional ethyl acetate. The organic layer and extracts were combined, treated with charcoal and dried over magnesium sulfate. To the stirred ethyl acetate was added approx. one equivalent of sodium 2-ethyl hexanoate in 811 ml of ethyl acetate. After 1.25 hours of stirring, the precipitated solids were filtered and dried to give 262 g of sodium 6-jS-bromopenicillanate.

To further purify the compound, the above sodium salt was dissolved in 1300 ml of deionized water, and the pH was adjusted to 1.3 at 6-8°C. The precipitated solid was stirred for 1.5 hours at 6-8°C and was filtered and washed with 300 ml of water. The free acid was treated with 2 liters of ethyl acetate and 200 ml of water, and the pH was adjusted with 6N hydrochloric acid to 1.35-1.40. The organic layer was separated and dried over magnesium sulfate. 802 ml of ethyl acetate containing approx. one equivalent of sodium 2-ethyl hexanoate. The precipitated sodium salt was stirred for 1 hour at room temperature and was filtered and dried to give 227 g of the desired crystalline sodium salt.

A sample of 40 g of the above sodium salt was added to 200 ml of water and the resulting solution was treated at ice bath temperature with 6N hydrochloric acid until a pH of 1.6. The precipitated free acid was filtered and resuspended twice in water. Drying in vacuo at room temperature overnight gave 34.05 g of the desired crystalline compound, m.p. 190-195°C (decomposition). Analysis.

Calcd for CgHl0N03SBx: C, 34.3 H, 3.6 N, 5.0 Found; C, 34.4 H, 3.7 N, 5.0

la] D +292°.

Example 34

6- j3- bromopenicillanic acid- sulphoxide- sodium salt

To 255 mg of sodium 6-/3-bromopenicillanate in 5 ml of water was added 182 mg of sodium periodate, and the resulting solution was stirred at room temperature for 3 hours. Ethyl acetate (30 mL) was added to the reaction solution, and sufficient 6N hydrochloric acid was added to adjust the pH to 1.3. The ethyl acetate layer was separated, backwashed with a saturated salt solution and dried over magnesium sulfate. The solvent was removed in vacuo and the remaining product was then dissolved in water containing one equivalent of sodium bicarbonate. Freeze-drying of the aqueous solution gave 235 mg of the desired product as a sodium salt.

Example 35

6- ft- bromopenicillanic acid- sulfone- sodium salt

To a solution of 255 mg of sodium 6-/3-bromopenicillanate i

140 mg of potassium permanganate and 0.11 ml were added to 5 ml of water

phosphoric acid in 3 ml of water while the pH was maintained at 6.0-6.4 by careful addition of aqueous sodium hydroxide. The reaction mixture was stirred at 0-5°C for 15-20 minutes and was then treated with 50 ml of ethyl acetate. The pH was adjusted to 1.5 with 6N hydrochloric acid, and 330 mg of sodium bisulfite was added in one portion. The pH was adjusted to 1.7, and the ethyl acetate layer was separated and backwashed with a saturated salt solution..Removal of the solvent

in vacuo gave the product as one oil, 216 mg.

The free acid, suspended in 10 ml of ethyl acetate, was added to 10 ml of water containing 57 mg of sodium bicarbonate. The aqueous layer was separated and lyophilized to give 140 mg of the desired compound as the sodium salt.

Example 36

6-/ 3-bromopenicillanic acid sulphonate sodium salt

6- bromo- 6- j odpenicillanic acid

To 10 ml of 2.5 N sulfuric acid, 6.21 g of iodobromide and .2.76 g of sodium nitrite in 75 ml of methylene chloride cooled to 0 to -5°C, was added 4.32 g of 6-/3-aminopenicillanic acid during of a period of 15 minutes. After 20 minutes of stirring at -5°C, 100 ml of 10% sodium bisulphite was added, and care was taken to keep the temperature of the reaction mixture below 10°C. The layers were separated and the aqueous extracted with methylene chloride

(3 x 50 ml). The combined organic layers and extracts were washed with brine, dried over magnesium sulfate and concentrated in vacuo to give 5.78 g of the desired intermediate, m.p. 145-147°C.

6- bromo- 6- iodopenicillanic acid sulfone

To 4.05 g of 6-bromo-6-iodopenicillanic acid in 30 ml of methylene chloride and overlaid with 60 ml of water was added sufficient 3N sodium hydroxide to give a pH of 7.0. The aqueous layer was separated, cooled to 5°C and treated dropwise over a 15 minute period with 1.93 g of potassium permanganate and 1 ral of 85% phosphoric acid in 30 ml of water. The pH was maintained at 5.8-6.2 by the addition of 3N sodium hydroxide, and the temperature was maintained at approx. 5°C. After the addition was complete, 100 ml of ethyl acetate was added and the pH was reduced to 1.5 with 6N hydrochloric acid. A 10% sodium sulfite solution (30 mL) was added until the reaction mixture turned pale yellow. The organic layer was separated and the aqueous extracted with ethyl acetate (4 x 50 mL). The organic layer and extracts were combined, washed with brine, dried over magnesium sulfate and concentrated under reduced pressure to give 3.6 g, m.p. 151-153°C.

6-ft-bromopenicillanic acid sulphone sodium salt To a solution of 3.36 g of 6-bromo-6-iodopenicillanic acid sulphone

in 130 ml of toluene at 5°C, under a nitrogen atmosphere, 1.09 ml of triethylamine was added, followed by 1.3 g of dimethyl-t-butylsilyl chloride. Stirring was maintained for 5 minutes at 5°C, 60 minutes at 25°C and 30 minutes at 45°C, and then the reaction mixture was cooled to 25°C. The triethylamine hydrochloride was removed by filtration, and 15 mg of azobisisobutyronitrile and 2.04 ml of dibenzylphenyltin hydride were added to the filtrate. The mixture was irradiated with ultraviolet light for 15 minutes, with external cooling to maintain the temperature at ca. 20-25°C. The solvent was removed in vacuo and the remaining material was dissolved in a 1:1 mixture of tetrahydrofuran-water. The pH was adjusted to 7.0 and the tetrahydrofuran was removed under reduced pressure. The aqueous layer was treated with 100 ml of ethyl acetate, and the pH was adjusted to 1.8 with 6N hydrochloric acid. The organic layer was separated, and the aqueous was further extracted with ethyl acetate. The organic layer and. extracts were combined, backwashed with a saturated saline solution and dried over sodium sulfate. The organic solution was then treated with 2.2 g of sodium 2-ethyl hexanoate in ethyl acetate and stirred for 1 hour. The resulting precipitated salt was filtered and dried.

Example 37

6-| 3- bromopenicillanic acid- acetoxymethyl .- ester

6, 6-dibromopenicillanic acid acetoxymethyl ester To a solution of 5 g of 6,6-dibromopenicillanic acid and 900 mg of di-isopropylethylamine in 50 ml of acetone and 50 ml of acetonitrile was added 0.7 ml of acetoxymethyl bromide, and the resulting solution was stirred at room temperature in 48 hours. A further 0.7 ml of the bromide and 900 mg of the amine were then added and stirring was continued for a further 48 hours. The solvent was removed in vacuo and the residue was treated with ethyl acetate and filtered. The filtrate was washed with water, IN hydrochloric acid and. saturated aqueous sodium bicarbonate, and then dried over sodium sulfate. The residue remaining after solvents were removed under vacuum was chromatographed on silica gel using methylene chloride as eluent. The fractions containing the desired material were combined and concentrated to give a colorless oil which solidified on standing. Recrystallization of a portion gave an analytical sample, m.p. 79-82°C. The NMR spectrum of -(CDCl 3 ) showed

absorption at 5.78 (s, 3H), 4.51 (s, 1H), 2.10 (s, 3H), 1.61 (s, 3H) and 1.48 (s, 3H) ppm.

6-/ 3- bromopenicillanesvre- acetoxymethyl- ester

A mixture of 430 mg of 6,6-dibromopenicillanic acid acetoxymethyl ester and 350 mg of triphenyltin hydride was heated under a nitrogen atmosphere to 90°C for 5 hours. The residue was chromatographed on 120 g of silica gel. using methylene chloride as eluent. Fractions containing the product were combined and concentrated in vacuo to give the desired product. The NMR spectrum (CDCl 3 ) showed absorption at 5.81 (s, 2H) 5.65 (s, 2H), 4.51 (s, 1H), 2.05 (s, 3H), 1.65 (s, 3H) and 1.48 (s, 3H) ppm.

Example 38

6- ff- bromopenicillanic acid pivaloyloxy ethyl ester

6, 6-dibromopenicillanic acid pivaloyloxyethyl ester To a solution of 1.8 ml of pivaloyloxymethyl chloride and 5 g of 6,6-dibromopenicillanic acid in 15 ml of dimethylformamide at 0°C was added 1.9 ml of triethylamine, and the resulting reaction mixture was stirred at room temperature for 16 hours. The reaction mixture was poured into 150 ml of water and 150 ml of ethyl acetate, and the pH was adjusted to 2.0 with 6N hydrochloric acid. The organic phase was washed with water, aqueous sodium bicarbonate solution, and a saturated saline solution, and then dried over magnesium sulfate. Removal of the solvent in vacuo gave 4.7 g of a red solid which was purified by column chromatography, m.p. 98-99°C. The NMR spectrum (CDClg) showed absorption at 5.80 (s, 2H), 5.75 (s, 1H), 4.5 (s, 1H), 1.61 (s, 3H), 1.47 (s , 3H) and 1.21 (s, 9H) ppm.

6-bromopenicillanic acid pivaloyloxymethyl ester The reduction process used in example 37 was applied to 6,6-dibromopenicillanic acid pivalyloxymethyl ester to obtain the desired product. NMR of the product showed absorption at 5.85

(d, lH, J = 5Hz), 5.76 (d, lH, J = 5Hz ) , 5.56 (d, lH, J = 4Hz), 5.31 (d, 1H, J = 4Hz), 4 .53 (s, 1H) , 1.67 (s, 3H) , 1.49 (s, 3H)

• and 1.22 (s, 9H) ppm»

Example 39

Starting from 6,6-dibromopenicillanic acid and the appropriate halide, and using the procedure of Example 37, the following compounds were prepared:

Electricity 4

-CH(CH3)O2CCH3

-CH 2 O 2 CCH(CH 3 ) 2

-^020(^)^3

-CH(CH3)O2CCH3

-CH(CH3)O2C(CH2)4CH3

-C(CH 3 ) 2 O 2 CCH 3

-C(CH 3 ) 2 O 2 CC(CH 3 ) 3

<-C>4<H>3°2<*>-C4H5°2+:<-C>8<H>5°2<#>

-CH 2 O 2 COCH 3

-CH 2 O 2 COCH(CH 3 ) 2

-CH(CH3)O2CO(CH2)3CH3

-CH(CH3)O2COC2H5

-C(CH 3 ) 2 O 2 CO(CH 2 ) 2 CH 3

<*>4-Crotonolactonyl

+ Y-butyrolacton-4-yl

3-phthalidyl

Example 40

6- ft- bromopenicillanic acid

A. 6, 6-dibromopenicillanic acid dimethoxyphosphine ester

To a solution of 3.58 g of 6,6-dibromopenicillanic acid in 40 ml of methylene chloride was added 1.08 g of triethylamine, and the solution was treated with 1.28 g of dimethoxychlorophosphine and stirred for 30 minutes. The solvent was removed in vacuo and the residue treated with 125 ml of dry diethyl ether. The insoluble triethylamine hydrochloride was filtered and the ether removed under reduced pressure to give the desired intermediate.

B. 6- j3- bromopenicillanic acid

To 4.5 g of 6,6-dibromopenicillanic acid dimethoxyphosphine ester in 150 ml of dry toluene was added 3.4 g of di-n-butylphenyltin hydride, and the resulting reaction mixture was stirred at room temperature for 20 minutes. A saturated aqueous sodium bicarbonate solution (150 mL) was added to the reaction mixture and the organic phase was separated and discarded. The aqueous phase was further extracted with ethyl acetate (2 x 25 ral), and the pH was carefully adjusted to 1.5 with 6N hydrochloric acid. The acidified aqueous layer was extracted (3 x 50 mL) with ethyl acetate and the extracts combined, dried over magnesium sulfate and concentrated to give the desired product.

Example 41

A. Using the procedure of Example 40A, and starting from the appropriate 6,6-disubstituted penicillanic acid and the required phosphine chloride, the following compounds were prepared: 6-chloro-6-iodopenicillanic acid diphenylphosphine ester,

6,6-dibromopenicillanic acid di-n-propoxyphosphine ester, 6,6-dibromopenicillanic acid diethylphosphine ester,

diiodopenicillanic acid dimethoxyphosphine ester,

6-bromo-6-iodopenicillanic acid diphenylphosphine ester,

6-brora-6-iodopenicillanic acid di-n-propylphosphine ester, 6-bromo-6>-methoxypenicillanic acid diraethylphosphine ester, 6-bromo-6-n-butoxypenicillanic acid dimethoxyphosphine ester, 6-bromo-6 -ethoxypenicillanic acid phenylethylphosphine ester, 6-bromo-6-methylthiopenicillanic acid diphenylphosphine ester, 6-bromo-6-i~propylthiopenicillanic acid methylmethoxyphosphine ester, 6-chloro-6-iodopenicillanic acid diethoxyphosphine ester sulfoxide, 6-bromo -6-Iodopenicillanic acid di-i-propoxyphosphine ester sulfoxide, 6-bromo-6-methoxypenicillanic acid ethoxyphenylphosphine ester sulfoxide, 6-bromo-6-methylthiopenicillanic acid dimethoxyphosphine ester sulfoxide.

B. Starting from the above-mentioned compounds, and applying the method from example 40B, the following analogues were formed. weighed: 6-Æ-chloropenicillanic acid, 6-/3-bromopenicillanic acid, 6-j3-jodopenicillanic acid, 6-/3-methoxypenicillanic acid, 6-0-n-butoxypenicillanic acid, 6-/3-ethoxypenicillanic acid, 6-/3-methylthiopenicillanic acid .

Example 42

6-/ ?- Morpenicillanic acid

A. 6-Chloro-6-iodopenicillanic acid 3,5-di-t-butyl-4-hydroxybenzyl ester

To a solution of 3.62 g of 6-chloro-6-iodopenicillanic acid in 200 ml of dry methylene chloride was added 1.0 g of triethylamine, and the resulting solution was cooled to 0-5°C. Ethyl chloroformate (1.1 g) was added portionwise to the reaction mixture over a period of 15 minutes. The reaction mixture was kept at 0°C for 30 minutes and then treated with 2.36 g of 3,5-di-t-butylbenzyl alcohol. After stirring in the cold for 2 hours, the reaction mixture was allowed to warm to room temperature. Water (75 mL) was added to the reaction mixture and the organic phase was separated, dried over sodium sulfate and concentrated in vacuo to give the desired compound.

B. 6-/ 3- Chlorpenicillanic acid

10 mg of azobisisobutyronitrile and 1.5 ml of tri-n -butyl tin hydride. The mixture was stirred for 20 minutes. The solvent was removed under reduced pressure, and the residue was dissolved in a 1:1 tetrahydrofuran-water mixture to which 1.08 g of sodium 2-ethyl hexanoate in 20 ml of methanol was then added. After stirring at room temperature for 3 hours, ethyl acetate was added and the pH adjusted to 7.0. The ethyl acetate layer was separated, fresh ethyl acetate added to the aqueous phase and the pH adjusted to 1.5 with 6N hydrochloric acid. It. organic phase was separated, dried over sodium sulfate and concentrated to give the desired product.

Example 43

A. Starting from the required 6,6-disubstituted penicillanic acid and applying the procedure of Examples 42A and B, the following compounds were prepared: 6-j8-bromopenicillanic acid, 6-/3-iodopenicillanic acid, 6-/3-methylthiopenicillanic acid, 6-j8-n-butylthiopenicillanic acid, 6-/3-chloropenicillanic acid sulfoxide, 6-/3-bromopenicillanic acid sulfoxide and 6-/3-methylthiopenicillanic acid sulfoxide.

Example 44

6-/ 3- fluoropenicillanic acid

A. 6- bromo- 6- fluoropenicillanic acid phenacyl ester

To a solution of 2.98 g of 6-bromo-6-fluoropenicillanic acid and 1.99 g of phenacyl bromide in 40 ml of a lsl mixture of dry diethylformamide-tetrahydrofuran cooled to 0°C, was added dropwise over a period of 15 minutes added 1.4 ml of triethylamine. The cold reaction mixture was stirred for 3 hours and then treated with 100 mL of ethyl acetate and 100 mL of a saturated aqueous sodium bicarbonate solution. The aqueous phase was separated and discarded,

and fresh water was added to the organic phase. The pH was adjusted to 5.0 with 6N hydrochloric acid and the organic phase was separated, washed with brine, dried over sodium sulfate and concentrated in vacuo to give the desired product.

B. 6- ft- fluorpenic i11anic acid

A solution of 2.08 g of 6-bromo-6-fluoropenicillanic acid phenacyl ester in 60 ml of dry toluene under a nitrogen atmosphere and cooled to 0°C was treated with 1.59 g of dibenzylmethyltin hydride and 10 mg of azobisisobutyronitrile, and the resulting reaction mixture was heated to 50°C for 5 hours. The solvent was removed under vacuum and the residue was chromatographed on silica gel using methylene chloride as eluent. The fractions containing the product were combined and concentrated to dryness.

The remaining product was dissolved in 25 ml of dry diethylformamide and treated with 375 mg of potassium thiophenoxide in 4 ml of dimethylformamide. After stirring at room temperature for 2 hours, the reaction mixture was added to 60 ml of a saturated aqueous sodium bicarbonate solution. Ethyl acetate (60 ral) was added and the organic phase was separated and fresh ethyl acetate was added.

The pH of the aqueous phase was adjusted to 1.5 with 6N hydrochloric acid, and the organic phase was separated, washed with a saturated salt solution and dried over sodium sulfate. Removal of the solvent in vacuo gave the desired product.

Example 45

A. Starting from the appropriate 6,6-disubstituted penicillanic acid and the necessary α-halomethylcarbonyl reagent and applying the procedure from Example 44A, the 6-bromo-6-fluoropenicillanic acid acetonyl ester of the following compounds is obtained,

6-bromo-6-fluoropenicillanic acid propionyl methyl ester, 6,6-dibromopenicillanic acid cyanomethyl ester,

6,6-dibromopenicillanic acid methoxycarbd methyl ester, 6,6-dibromopenicillanic acid phenacyl ester,

6-chloro-6-hydropenicillanic acid phenacyl ester,

6-chloro-6-hydropenicillanic acid acetonyl ester,

6-chloro-6-iodpenicillanic acid propionyl methyl ester, 6-chloro-6-iodpenicillanic acid propoxycarbomethyl ester, 6,6-diiodpenicillanic acid cyanomethyl ester,

6,6-diiodopenicillanic acid i-butyrylmethyl ester,

6,6-diiodopenicillanic acid phenacyl ester,

6-bromo-6-iodopenicillanic acid acetonyl ester,

6-bromo-6-iodopenicillanic acid cyanomethyl ester,

6-bromo-6-methoxypenicillanic acid phenacyl ester,

6-bromo-6-methoxypenicillanic acid propionyl methyl ester, 6-bromo-6-methoxypenicillanic acid ethoxycarboraethyl ester, 6-bromo-6-methylthiopenicillanic acid cyanomethyl ester, 6-bromo-6-methylthiopenicillanic acid phenacyl ester,

6-chloro-6-iodopenicillanic acid n-butyrylmethyl ester sulfoxide, 6,6-dibromopenicillanic acid phenacyl ester sulfoxide, 6,6-diiodopenicillanic acid acetonyl ester sulfoxide, 6-bromo-6-iodopenicillanic acid cyanomethyl ester sulfoxide and 6-bromo-6-methoxypenicillanic acid methoxycarbomethyl ester sulfoxide.

B. By walking. starting from the esters from example 45A and applying the method from example 44B, the following congeners are prepared: 6-0-fluoropenicillanic acid, 6-/3-bromopenicillanic acid, 6-Æ-chloropenicillanic acid, 6-^-iodopenicillanic acid, 6-/3-raethoxypenicillanic acid, 6 -j3r-methylthiopenicillanic acid, 6, /3-bromopenicillanic acid sulfoxide and 6,0-methoxypenicillanic acid sulfoxide.

Example 46

6- ft- Chlorpenicillanic Acid Sulfoxide

A. O-(6-Chloro-6-iodopenicillanoyl) benzaldehyde oxime sulfoxide

To a solution of 3.9 g of 6-chloro-6-iodopenicillanic acid sulfoxide in 200 ml of methylene chloride was added 1.0 g of triethylamine, and the resulting reaction mixture was cooled to 0°C. Ethyl chloroformate (1.1 g) was added dropwise over a period of 15 minutes and the reaction mixture was kept at 0°C for 30 minutes. Benzaldehyde oxime (1.2 g) was added in 10 ml of dry acetone and stirring was continued for 2 hours. The reaction mixture was then set aside for to warm to room temperature and stirring was continued for a further 2 hours. The reaction mixture was filtered and the filtrate concentrated to dryness. The residue was partitioned between ethyl acetate (100 ml) and water (50 ml). The aqueous layer was separated and the organic layer was washed with a saturated aqueous sodium bicarbonate solution and was dried over magnesium sulfate. Removal of the solvent in vacuo gave the desired product.

B. 6- j3- chlorpenicillansvre- sulf oxide

To 2.48 g of 0-(6-chloro-6-iodopenicillanoyl)benzaldehyde oxime sulfoxide in 75 ml of dry toluene under a nitrogen atmosphere was added 1.62 g of dibenzyl-n-butyltin hydride and 15 mg of azobisisobutyronitrile. The resulting reaction mixture was stirred, heated to 50°C and held at this temperature for 5 hours. The solvent was removed in vacuo and the residue was partitioned between 100 ml of ethyl acetate and 75 ml of water. The organic phase was separated, dried over sodium sulfate and concentrated under reduced pressure to dryness. One and eight tenths of a gram of the residue was dissolved in .25 ml of dimethylformamide to which was then added 660 mg of potassium thiophenoxide in 10 ml of the same solvent. After stirring for 2 hours at room temperature, the reaction mixture was added to a saturated sodium bicarbonate solution. The aqueous liquid was extracted with 75 ml of ethyl acetate, and the organic phase was separated. The pH of the aqueous phase was adjusted to 1.5 with 6N hydrochloric acid and extracted with ethyl acetate. The organic phase was separated, dried over sodium sulfate and concentrated in vacuo to dryness to give the desired product.

Example 47

A. Using the method of Example 46A and starting from the appropriate 6,6-disubstituted'penicillanic acid and oxime, the following compounds were synthesized:

B.. Starting from the esters in example 47A and applying the procedure from example 46B, the following analogues were prepared: 6f)/3-fluprpenicillanic acid, 6-/3-chloropenicillanic acid, 6-/5-bromopenicillanic acid, 6-/3- iodopenicillanic acid, 6-Æ-methoxypenicillanic acid, 6-/3-methylthiopenicillanic acid, 6-/3-bromopenicillanic acid sulfoxide, 6-/3-methoxypenicillanic acid sulfoxide, 6-Æ-fluoropenicillanic acid sulfoxide and 6-/3-chloropenicillanic acid sulfoxide oxide.

Example 48

6-/3--j odpenicillanic acid

A. 6, 6- diiodopenicillanic acid benzhydryl ester

To a solution of 5.94 g of sodium nitrite in 250 ml of water at 5°C, 2.9 g of 6-/3-aminopenicillanic acid benzhydryl ester tosylate salt in 250 ml of methylene chloride was added while stirring. p-toluenesulfonic acid (1.2 g) was added in 3 portions over a period of 30 minutes and the mixture was stirred for 1 hour at room temperature. The organic phase was separated, dried over sodium sulfate and treated with 1.3 g of iodine. The resulting solution was stirred at room temperature for 4 hours and was then washed with an aqueous sodium thiosulfate solution and concentrated to a small volume. The residue was chromatographed on silica gel using petroleum ether with increasing proportions of ethyl acetate as eluent. The fractions containing the product were combined and concentrated in vacuo to give the desired product.

B. 6-ft- iodopenicillanic acid benzhydryl ester

To a solution of 1.92 g of 6,6-diiodopenicillanic acid benzhydryl ester in 8 ml of benzene was added 500 mg of triphenyltin hydride and 10 mg of azobisisobutyronitrile, and the resulting reaction mixture was stirred under a nitrogen atmosphere at 50°C for 1 hour. A further amount of hydride (500 mg) and nitrile (10 mg) was added and heating at 50°C continued for 3 hours. The solvent was removed under vacuum, and the residue was chromatographed over silica gel using petroleum ether with increasing proportions of ethyl acetate as eluent. The fractions containing the product were combined and concentrated to dryness. The NMR spectrum (CDCl 3 ) showed absorption at 7.50 (bs, 10H), 6.97 (s, 1H), 5.66 (d, 1H, AB, J = 4.0Hz), 5.44 (d, lH, AB,

J = 4.0Hz), 4.67 (s, 1H), 1.70 (s, 3H) and 1.40 (s, 3H) ppm.

C. 6-fi-j odpenicillanic acid

Trifluoroacetic acid (0.5 ml) was added to 80 mg of 6-(3-iodo-penicillanic acid-benzhydryl ester in 1 ml of methylene chloride) and the reaction mixture was stirred for 30 minutes at room temperature. The mixture was evaporated to dryness to give 76 mg of crude product. Purification was carried out by chromatography on silica gel.

Example 49

A. Starting from the appropriate penicillanic acid ester and applying the procedure of Example 48A, the following compounds were prepared:

B. By following the procedure from examples 48B and C and starting from the esters in example 49A, the following penicillanic acids are obtained: 6-/3-fluoropenicillanic acid, 6-/J-chloropenicillanic acid, 6-Æ-bromopenicillanic acid, 6-^j8- methoxypenicillanic acid, 6-/3-ethoxypenicillanic acid, 6-/3-methylthiopenicillanic acid, 6-/3-bromopenicillanic acid sulfoxide, 6-/8-fluoropenicillanic acid sulfoxide and 6-/3-chloropenicillanic acid sulfoxide.

Example 50

6- 0- j odpenicillanic acid

A. 6,6-Diiodopenicillanic acid 4-methoxybenzyl ester The title compound was prepared from 6-[3-aminopenicillanic acid 4-aminopenicillanic acid 4-methoxybenzyl ester by following the procedure of Example 48A.

v1

B. 6-/ 3- 1 odpenicillanic acid- 4- methoxyben2vl- ester

The title compound was prepared from 6,6-diiodopenicillanic acid ε-4-methoxybenzyl ester using the procedure of Example 48B. The NMR spectrum (CDCl3) showed absorption at 7.36 (d, 2H, AA', XX', J = 9Hz) , 6.95 (d, 2H, AA' , XX', J = 9.0Hz) , 5 .65 (d, 1H, AB, J = 4.2Hz), 5.42 (d, lH, AB, J = 4.2Hz), 4.58 (s, lH), 3.89 (s, 3H) , 1.71 (s, 3H), 1.70 (s, 3H) and 1.39 (s, 3H) ppm.

C. 6-/3-j odpenicillanic acid

6-(3-Iodopenicillanic acid 4-methoxybenzyl ester) (90 mg) was dissolved in 2 ml of methylene chloride to which 1 ml of trifluoroacetic acid and 3 drops of anisole were then added. The mixture was stirred at room temperature for 5 hours and then evaporated to dryness. The residue was chromatographed on silica gel using petroleum ether and then ethyl acetate as eluent. The fractions containing the product were combined and concentrated to give 40 mg of the desired product. The NMR spectrum (CDCl^) showed absorption at approx.

9 (bs, 1H) , 5.65 (d, 1H, AB, J = 4.0Hz) , 5.39 (d, 1H, AB,

J = 4.0Hz), 4.57 (s, 2H), 1.74 (s, 3H) and 1.57 (s, 3H).

Example 51

A. Starting from the appropriate penicillanic acid ester and applying the procedure of Example 49A, the following compounds were prepared:

B. Starting from the compounds in Example 51 and following the procedures in Examples 48B and C, the following analogues are obtained:

6-bromo-6-methylthiopenicillanic acid tri-n-butyltin ester,

6-bromo-6-chloropenicillanic acid tribenzyltin ester sulfoxide,

6,6-dibromopenicillanic acid tri-n-butyltin ester sulfoxide, 6,6-diiodopenicillanic acid tri-n-propyltin ester sulfoxide, and 6-bromo-6-chloropenicillanic acid triphenyltin ester sulfoxide.

B. Using the reagents of Example 53A and using the procedure of Example 52B, the following 6-/3-substituted penicillanic acids were prepared: 6-/3^-bromopenicillanic acid, 6-O-chloropenicillanic acid, 6-/3-iodopenicillanic acid , 6-jS-chloropenicillanic acid sulfoxide, 6-β-bromopenicillanic acid sulfoxide, and 6-β-iodopenicillanic acid sulfoxide.

Example 54

6- ft- bromopenicillanic acid

A. 6, 6-dibromopenicillanic acid methyl acetoacetate ester

To 5.0 g of 6,6-dibromopenicillanic acid sodium salt in 100 ral of dimethylformamide was added 1.6 ml of methyl 2-chloroacetoacetate, and the resulting reaction mixture was stirred overnight at room temperature. The mixture was poured into 400 ml of ice and water and extracted with ethyl acetate. The organic phase was separated and washed successively with water, a saturated aqueous sodium bicarbonate solution and a saline solution. The organic phase was then dried

over magnesium sulfate and concentrated to a dark oil (5.0 g), which was chromatographed on 300 g of silica gel. The fractions of eluent, which comprised toluene/ethyl acetate (2:1, vol.:vol.), containing the product were combined and concentrated in vacuo,

and this gave 4.0 g of the desired product.

B. 6-/ 3- bromopenicillanic acid

Under anhydrous conditions and in a nitrogen atmosphere, 2.0 g of 6,6-dibromopenicillanic acid methyl acetoacetate ester in 140 ml of dry

benzene treated with 1.1 ral tri-n-butyltin hydride, and the resulting reaction mixture was stirred overnight at room temperature.

The benzene solvent was removed in vacuo and the residue slurried in hexane. The undissolved material was chromatographed on 250 g of silica gel using toluene/ethyl acetate (5:1, vol.:vol.) as eluent. The fractions containing the desired product were combined and concentrated under reduced pressure to dryness.

Example 52

6- ft- bromopenicillanic acid- sodium salt

A. 6, 6-dibromopenicillanic acid tri-n-butyltin ester

To a slurry of 35.9 g of 6,6-dibromopenicillanic acid in 700 ml of toluene was added 29>5 g of bis(tri-n-butyltin)oxide, and the resulting mixture was heated to reflux. During a period of approx. At 45 minutes, the toluene was distilled from the reaction mixture, and water was azeotropically removed during this time period. The remainder of the solvent was removed at room temperature in vacuo, and this gave 78.7 g of the desired intermediate.

B. 6-/ ?- bromopenicillanic acid sodium salt

To 1.0 g of 6,6-dibromopenicillanic acid tri-n-butyltin ester in 5 ml of toluene, 0.4 ml of tri-n-butyltin hydride was added dropwise at 55°C. Heating was continued for 3.5 hours, after which the solvent was removed and the residue dissolved in 25 ml of chloroform. The chloroform was washed with a saturated sodium bicarbonate solution (2 x 50 mL). The aqueous washings were combined, the pH was adjusted to 1.5 with 6N hydrochloric acid, and the product was extracted with ethyl acetate. The ethyl acetate extracts were combined, dried over magnesium sulfate, and 1.24 mL (1.24 mmol/cc) of ethyl acetate containing sodium 2-ethylhexanoate was added. After stirring in the cold for 1 hour, the product was filtered and dried, 114 mg.

Example 53

A. Starting from the appropriate 6,6-disubstituted penicillanic acid and tin oxide, and applying the procedure of Example 52A, the following tin esters were prepared: 6,6-dibromopenicillanic acid triethyltin ester,

6,6-dibromopenicillanic acid triphenyltin ester,

6,6-dibromopenicillanic acid diphenylbenzyltin ester, 6-bromo-6-chloropenicillanic acid triphenyltin ester,

6-bromo-6-chloropenicillanic acid tri-i-propyltin ester, 6-iod-6-chloropenicillanic acid tri-n-butyltin ester, 6-iod-6-chloropenicillanic acid dibenzylphenyltin ester, 6,6- diiodopenicillanic acid—triphenyltin ester,

6-iodo-6-bromopenicillanic acid triethyltin ester,

To 3.9 g of 6-/3-bromopenicillanic acid methyl acetoacetate ester, prepared by the above procedure, in 50 ml of acetone, 2.1 g of sodium uranium nitrite in 10 ml of water was added with stirring. After stirring for 3 hours at room temperature, the solvent was removed in vacuo and the remaining aqueous liquid was extracted once with ether. The aqueous liquid was then acidified to a pH of 1.5 with 6N hydrochloric acid and extracted with ethyl acetate. The organic phase was dried over sodium sulfate and concentrated under reduced pressure to give the desired product.

Example 55

Using the procedure from Example 54A, and starting from the necessary 6,6-disubstituted penicillanic acid sodium salts, the following esters were prepared:

B. Starting from the esters of Example 53A and applying the procedure of Example 54B, the following compounds were synthesized:

Example 56

6/ 3- fluoromethylpenicillanic acid sulfone

A. Benzyl- 6- bromo- 6- hydroxymethylpenicillanate

A solution of 44.9 g of benzyl-6,6-dibromopenicillanate in 600 ml of dry tetrahydrofuran was cooled to -78°C, and 56.4 ml of t-butyl magnesium chloride was added dropwise with vigorous stirring in an inert atmosphere while the temperature was kept at -60°C. After stirring for 30 minutes at -78°C, the solution was treated with gaseous formaldehyde in a stream of nitrogen until 5 molar equivalents had been added. The reaction mixture was quenched at -78°C by dropwise addition of 5.7 ml of acetic acid over a period of 25 minutes. The reaction solution was allowed to warm to room temperature and was concentrated in vacuo. 200 ml of water and 200 ml of ethyl acetate were added to the reaction mixture. The organic layer was separated, and the aqueous layer was again extracted with ethyl acetate. The organic phases were combined, washed successively with water (200 mL), 5% aqueous sodium bicarbonate (200 mL) and brine (200 mL), and dried over magnesium sulfate. Removal of the solvent under reduced pressure afforded 38.2 g of the desired product, epimeric at C-6.

B. Benzyl-6-fluoromethyl-6-bromopenic acid

To a cooled (-78°C) solution of 3.2 g of diethylaminosulfur trifluoride in 80 ml of dry methylene chloride kept in an atmosphere of nitrogen, 8.05 g of benzyl-6-bromo-6-hydroxymethylpenicillanate in 20 ml of methylene chloride were added and 3.2 ml of pyridine. The resulting reaction mixture was stirred in the cold for 45 minutes and allowed to warm to room temperature. The reaction solution was washed with water (2 x 100 ml) and a saline solution (2 x 100 ml) and dried over magnesium sulfate. The organic layer was then concentrated to dryness in vacuo. The remaining material, 6.4 g, was dissolved in 20 ml of toluene-ethyl acetate (4:1) and chromatographed on a silica gel column using toluene-ethyl acetate (4:1) as eluent. Fractions 12 to 38 were combined and concentrated to dryness to give 3.54 g of product.

C. Benzyl-6/3-fluoromethylpenicillanate

To 3.5 g of benzyl-6-fluoromethyl-6-bromopenicillanate in 80 ml of dry benzene kept under a nitrogen atmosphere was added 2.28 ml of tri-n-butyltin hydride, and the resulting reaction mixture was heated to reflux. After 1.5 hours, the reaction mixture was cooled to room temperature and concentrated to an oil,

2.1 g. The remaining oil was dissolved in toluene - ethyl acetate (4:1) and was chromatographed on a silica gel column using toluene - ethyl acetate as eluent. Fractions 33 to 46 were combined and concentrated to give 1.8 g of the product as an oil.

D. Benzyl-6/3-fluoromethylpenicillanate sulfone

To 20 ml of methylene chloride was added 485 mg of benzyl-60-fluoromethylpenicillanate and the resulting solution was cooled to 0°C. m-Chlorobenzoic acid (85%) (853 mg) was added in portions and the reaction mixture was stirred for 2 hours in the cold<p>g then stirred at room temperature overnight. The solvent was removed in vacuo, and the residue was partitioned between ethyl acetate -> water (1:1).

The pH of the mixture was adjusted to 7.2 with sodium bicarbonate solution, and sufficient sodium bisulfite was added until a negative starch-iodine test was obtained. The organic phase was separated and washed successively with a saturated sodium bicarbonate solution and a saturated saline solution, and dried over magnesium sulfate. Removal of the solvent under reduced pressure gave 400 mg of the product.

E. 6/ 3- fluoromethylpenicillanic acid sulfone

To a suspension of 365 mg of 5% palladium-on-calcium carbonate, under reduced conditions with hydrogen at 3.50 kg/cm 2 for 20 minutes, in 20 ml of methanol - water (1:1) was added 356 mg of benzyl -6j8-fluoromethylpenicillanate-sulfone, and the mixture was shaken in a hydrogen atmosphere at an initial pressure of 3.36 kg/cm<2> for one hour- The catalyst was filtered off and the filtrate was freeze-dried, and this gave 220 mg of the final product which the calcium salt.

The NMR spectrum (D 2 O) showed absorption at 1.45 (s, 3H), 1.57 (s, 3H), 4.2 (s, 1H), 4.4 and 4.9 (d, m, 1H) , 5.1 (d, lH,

J = 4Hz), 4.6 and 5.4 (d, m, 2H) ppm.

Example 57

6/ 3- chloromethylpenicillanic acid sulfone

A. Benzyl-6tf- hydroxymethylpenicillanate

A solution containing 10 g of benzyl-6-bromo-6-hydroxymethylpenicillanate (Example 56A), 6.9 ml of tri-n-butyltin hydride and traces of azobisisobutyronitrile in 200 ml of benzene was refluxed for 5 hours under nitrogen. The reaction mixture was cooled and concentrated in vacuo. The residue was triturated with hexane and chromatographed on silica gel, using toluene/ethyl acetate (2:1) as eluent, and this gave 7.5 g of the product.

B. Benzyl-6ff-chloromethylpenicillanate

A solution of 1.28 g of benzyl 60-hydroxymethylpenicillanate and 1.88 g of triphenylphosphine in 5 ml of carbon tetrachloride was stirred at room temperature for 2 hours. The reaction mixture was treated with diethyl ether, and the solid from the resulting slurry was filtered and chromatographed on 75 g of silica gel using toluene-ethyl acetate as eluent. Fractions 20 to 24 were combined and concentrated to give 358 mg of product.

The NMR spectrum (CDCl 2 ) showed absorption at 1.42 (s, 3H), 1.6 (s, 3H), 3.83 (m, 3H), 4.4 (s, 1H), 5.18 (s, 2H), 5.4 (d,

1H, J = 4Hz) and 7.37 (s, 5H) ppm.

C. Benzyl- 6ft- chloromethylpenicillanate?>suiphon

To a cold solution (0-5°C) of 200 mg of benzyl-6/3-chloromethylpenicillanate in 30 ml of methylene chloride, 300 mg of 85% strength m-chloroperbenzoic acid was added in portions under a nitrogen atmosphere. The resulting mixture was stirred overnight and then concentrated to dryness. The residue was partitioned between water - ethyl acetate (1:1) and the pH was adjusted to 7.2 with sodium bicarbonate. Sufficient sodium bisulfite was added to destroy the excess peracid and the organic layers were separated, washed with a saturated sodium bicarbonate solution and saturated saline solution, and dried over magnesium sulfate. Removal of the solvent in vacuo gave 189 mg of the product as an oil.

The NMR spectrum (CDCl 3 > showed absorption at 1.3 (s, 3H), 1.52 (s, 3H), 3.6 (ra, 1H), 3.9 (m, 2H), 4.5 (s, 1H ), 4.59 (cl, lH,

J = 4Hz), 5.22 (ABq, 2H, JAB «= 12Hz) and 7.35 (s, 5H) ppm.

D. 6ft- chloromethylpenicillanic acid- sulfone

189 mg of benzyl-6 /3-chloromethylpenicillanate sulfone, and the resulting suspension was shaken in a hydrogen atmosphere at an initial pressure of 3.50 kg/cm 2 for 40 minutes. The catalyst was filtered off and the filtrate concentrated under reduced pressure to dryness to give 125 mg of the final product as the calcium salt.

The NMR spectrum (D 2 O) showed absorption at 1.41 (s, 3H), 1.57 (s, 3H), 4.0 (ra, 3H), 4.22 (s, 1H) and 5.05 (d , 1H.J=4Hz) ppm.

Example 58

6/ 3- broraarethylpenicillanic acid sulfone

A. Benzyl- 6/ 3- bromomethylpenicillanate

To a solution of 830 mg of benzyl-6/3-hydroxymethylpenicillanate and 2.2 g of carbon tetrabromide in 5 ml of methylene chloride cooled to 0-5°C and under one nitrogen atmosphere, 1.47 g of triphenylphosphine in 5 ml of methylene chloride was added dropwise. After stirring for 1 hour in the cold, the reaction mixture was chromatographed on silica gel using methylene chloride as eluent. Fractions 4 to 11 were combined and concentrated to give 580 mg of product as an oil.

The NMR spectrum (CDC<_>3) showed absorption at 1.42 (s, 3H), 1.60 (s, 3H), 3.6 (m, 2H), 3.9 (ra, 1H), 4 .40 (p, lH), 5.18

(s, 2H), 5.4 (d, 1H, J = 4Hz) and 7.37 (s, 5H) ppm.

B. Benzyl-6/3-bromoethylpenicillinate sulfone

To a solution of 250 mg of benzyl-6-bromomethylpenicillanate in 30 ml of methylene chloride cooled to 0~5°C and kept under a nitrogen atmosphere, 330 mg of 85% m-chloroperbenzoic acid was added. After stirring at 0-5°C for 2 hours, the reaction mixture was stirred at room temperature overnight. The solvent was removed under reduced pressure, and the residue was partitioned between water - ethyl acetate (1:1). The pH was adjusted to 7.2 with a saturated sodium bicarbonate solution, and sufficient sodium bisulfite was added to destroy residual peracid. The organic layer was washed with a saturated sodium bicarbonate solution followed by saturated saline solution and drying over magnesium sulfate. Removal of the solvent in vacuo gave 220 mg of the product as an oil.

The NMR spectrum (CDCl 3 ) showed absorption at 1.29 (s, 3H), 1.55 (s, 3H), 3.5 (m, 2H), 3.9 (m, 1H), 4.5 ( pp, lH). 4.59 (a, 1H, J = 4Hz), 5.22 (ABq, 2H, JAB = 12Hz) and 7.35 (s, 5H) ppm.

C. 6/ ?- bromomethylpenicillanic acid sulfone

A suspension of 290 mg of benzyl-6/3-bromomethylpenicillanate-fv:.". sulfone and 300 mg of 5% ig palladium-on-calcium carbonate, previously reduced with hydrogen at 3.50 kg/cm 2 for 20 minutes, for 20 ml of methanol - water (1:1) was shaken in a hydrogen atmosphere at an initial pressure of .3.50 kg/cm 2 for 35 minutes. The catalyst was filtered off and the methanol was removed from the filtrate in vacuo. The remaining aqueous solution was extracted with ethyl acetate and

was freeze-dried, and this gave 200 mg of the product as the calcium salt.

The NMR spectrum (D 2 O) showed absorption at 1.4 (s, 3H), 1.60 (s, 3H), 3.8 (m, 2H), 4.0 (m, 1H), 4.2 (s , lH) and 5.0 (d, lH, J =. 4Hz) ppm.

Example 59

6ft- chloromethylpehicillanic acid

To a suspension of 300 mg of 5% palladium-on-calcium carbonate, previously reduced with hydrogen at 3.50 kg/cm 2 for 20 minutes, in 20 ml of methanol - water (1:1) was added 300 mg

benzyl-6£-chloromethylpenicillanate (Example 57B), and the resulting suspension was shaken in a hydrogen atmosphere at an initial pressure of 3.50 kg/cm 2 for 45 minutes. A further 300 mg of catalyst was added and the hydrogenation continued for 35 minutes. The catalyst was filtered off and the methanol removed

in vacuo from the filtrate. The aqueous residue was extracted with ethyl acetate and freeze-dried to give 220 mg of the product as the calcium salt.

The NMR spectrum (D 2 O) showed absorption at 1.52 (s, 3H), 1.62 (s, 3H), 3.95 (m, 3H), 4.2 (s, 1H) and 5.4 (d , 1H, J = 4Hz) ppm.

■i<*>

In a similar way, starting from benzyl-6/3-fluoromethylpenicillanate and benzyl-6/3-bromomethylpenicillanate, 6/ ?-fluoromethylpenicillanic acid and 6/ 3- bromomethyl-penicillan<y>re were prepared, respectively.

Example 60

6ft- fluoromethylpenicillanic acid- sulfoxide

A. Benzyl-6/3-fluoromethylpenicillanic acid sulfoxide

To a solution of 323 mg of benzyl-60-fluoromethylpenicillanate in 25 ml of dry methylene chloride at 0°C, 240 mg of 85% m-chloroperbenzoic acid was added in portions. After two hours the cooling bath was

removed, and the reaction mixture was stirred at room temperature overnight. The solvent was removed in vacuo, and the residue partitioned between ethyl acetate and water (1:1) at pH 7.5. The organic phase was separated, washed with a saturated sodium bicarbonate and salt solution and dried over magnesium sulfate. Removal of the solvent gave the desired product.

B. 6ft- fluoromethylpenicillanic acid- sulphoxide

A suspension of 400 mg of 5% palladium-on-calcium carbonate,

o o '2

previously reduced with hydrogen at 3.50 kg/cm for 20 minutes, and 400 mg of benzyl-60-fluoromethylpenicillanate in 20 ml of methanol - water (1:1) was shaken in a hydrogen atmosphere at an initial pressure of 3.50 kg/ cm for one hour. The catalyst was filtered off and the methanol removed from the filtrate. The aqueous residue was extracted with ethyl acetate and then acidified to pH 1.5 with dilute 6N hydrochloric acid. Fresh ethyl acetate was added, and the organic phase was separated, washed with a saturated salt solution and dried over magnesium sulfate. Removal of the solvent in vacuo gave the desired compound as the free acid.

By starting from benzyl r-6-chloromethylpenicillanate or b,benzyl-6-bromomethylpenicillanate and using the above-mentioned methods, 6-chloromethylpenicillanic acid sulfoxide and 6-bromomethylpenicillanic acid sulfoxide are obtained, respectively.

Example 61

6/ 3-Hvdroxymethylpenicillanic acid sulfone

A. Benzyl- 6/ 3- hydroxymethyl penicillanate sulfone

m-Chloroperbenzoic acid (11.8 g) was added to a solution of 7.5 g of benzyl-6S-hydroxymethylpenicillanate (Example 57A) in 600 ral of methylene chloride cooled to 0-5°C. The solution was then allowed to warm to room temperature and was stirred for 5 hours. The solvent was removed in vacuo and the residue was partitioned between 200 ml of water and 200 ml of ethyl acetate. The pH of the mixture was adjusted to 7

By adding a saturated sodium bicarbonate solution, and sufficient sodium bisulphite was added to give a negative peroxide test (starch-iodine). The layers were separated and the aqueous was washed with ethyl acetate. The organic layer and washing liquids were combined, washed successively with water, 5% sodium bicarbonate solution and saline solution and dried over magnesium sulfate. Removal of the solvent under reduced pressure gave a foam, which by chromatography on silica gel (chloroform - ethyl acetate 20:3) gave 3.5 g of the desired intermediate.

B. Calcium- 6/ 3- hydroxymethylpenicillanate- sulfone

To a 30 ml solution of water - methanol (1:1) was added 3.5 g of 5% palladium-on-calcium carbonate, and the catalyst had previously been hydrogenated at 3.29 kg/cm 2 in a hydrogenation apparatus. To the resulting catalyst was added 3.5 g of benzyl 6j3-hydroxymethylpenicillanate sulfone in 10 ml of methanol and 20 ml of tetrahydrofuran, and the mixture was shaken in a hydrogen atmosphere at 3.36 kg/cm 2 for 30 minutes. The catalyst was filtered off with a filter aid and the filtrate was concentrated in vacuo, the clear aqueous residue was extracted with ethyl acetate (2 x 100 ml) and freeze-dried, and this gave 3.0 g of the desired product as the calcium salt.

The NMR spectrum (CDCl3- free acid) showed absorption at 1.49 (s, 3H), 1.6 (s, 3H), 4.1 (m, 3H), 4.32 (s, 1H) and 4, 9 (d, lH,

J = 4Hz) ppm.

Example 62

6ft- hydroxymethylpenicillanic acid sulfoxide

A. To a solution of 7.5 g of benzyl-6/3-hydroxymethylpenicillanate (Example 57A) in 500 ml of dry methylene chloride cooled to 0-5°C was added 5.9 g of m-chloroperbenzoic acid in portions. The solution was then allowed to warm to room temperature and was stirred overnight. The solvent was removed in vacuo, and the residue was treated with water - ethyl acetate (1:1). The pH of the mixture was adjusted to 7.2 and sufficient sodium bisulfite was added to destroy any remaining peracid. The organic layer was separated, washed successively with water, 5% sodium bicarbonate solution and a saturated saline solution, and dried over magnesium sulfate. Removal of the solvent under reduced pressure gave the desired product.

Example 63

Pivalovloxymethyl- 6fi- hydroxymethylpenicillanate- sulfone

To a solution of 1.0 g of 6/3-hydroxymethylpenicillanic acid sulfone sodium salt in 10 ml of dimethylformamide, cooled to 0-5°C, was added 0.52 ml of chloromethyl pivalate. After stirring overnight at room temperature, the reaction mixture was poured into a mixture of water - ethyl acetate. The ethyl acetate layer was separated, backwashed with water (3 x 100 ml) and brine (3 x 50 ml) and dried over magnesium sulfate. The solvent was removed in vacuo to give 1.1 g of the product as an oil.

The NMR spectrum (CDCl^) showed absorption at 1.27 (s, 9H), 1.42 (s, 3H), 1.6 (s, 3H), 2.9 (bs, 1H), 4.2 ( m, 3H), 4.58

(s, 1H) , 4.75 (m, 1H) and 5.82 (ABq, 2H, 8ft--8 = 16Hz) ppm.

Example 64

Starting from the appropriate 60-hydroxymethylpenicillanic acid, -sulfoxide or -sulfone and the necessary halide and applying the procedure from Example 63, the following intermediate compounds were prepared:

4-crotonolactonyl

Y-butyrolacton-4-yl

#3-phthalidyl

Example 65

Pivaloyloxymethyl- 6ff- fluoromethylpenicillanate- sulfone

To a solution of 3.2 g of diethylaminosulfur trifluoride in 80 ml of dry methylene chloride cooled to -78°C and maintained under a nitrogen atmosphere was added 7.5 g of pivaloyloxymethyl-6-hydroxymethylpenicillanate sulfone (Example 63) in 20 ml of methylene chloride containing 3.2 ml of pyridine. The reaction mixture was stirred in the cold for 45 minutes and then allowed to warm to room temperature. The reaction solution was washed with water (2 x 100 ml) and a saturated saline solution (2 x 100 ml) and dried over magnesium sulfate. The organic phase was separated and concentrated to dryness. The remaining material was chromatographed on silica gel and the fractions containing the product were combined and concentrated to give the desired material.

Example 66

Pivalovloxvmethyl- 6ff- chloromethylpenicillanate- sulfoxide

A solution of 1.88 g of triphenylphosphine and 1.44 g of pivaloyloxymethyl-6/3-hydroxymethylpenicillanate sulfoxide (Example 64) in 6 ml of carbon tetrachloride was stirred at room temperature for 3 hours. The reaction mixture was treated with diethyl ether and the resulting solid was filtered and chromatographed on silica gel. The fractions containing the desired material were combined and concentrated in vacuo to give the desired product.

Example 67

Acetoxymethyl- 6ft- bromomethyl penicillanate

To a solution of 788 mg of acetoxymethyl-6/8-hydroxymethylpenicillanate and 2.2 g of carbon tetrabromide in 6 ml of methylene chloride, cooled to 0°C and under a nitrogen atmosphere, 1.47 g of triphenylphosphine in 5 ml of methylene chloride was added dropwise. After stirring for 2.5 hours in the cold, the reaction mixture was treated with diisopropyl ether, and the solid was filtered and chromatographed on silica gel. The fractions containing the desired material were combined and concentrated in vacuo to give the desired product

.product.

Example 68

Starting from the appropriate 6/3-hydroxymethylpenicillanate ester and applying the procedure from the given example, the following compounds were prepared:

Example 69

6/ 3- f luorme tylpenicillans yre

A. 6/ 3- Hydroxymethylpenicillanic acid ph enacyl ester

To a solution of 2.31 g of 60-hydroxymethylpenicillanic acid and 1.98 g of phenacyl bromide in 40 ml of a 1:1 mixture of dry dimethylformamide-tetrahydrofuran, cooled to 0°C, 1.4 ml of triethylamine was added dropwise during a period of 15 minutes. The cold solution was stirred for 3.5 hours and then treated with

125 ml of ethyl acetate and 100 ml of a saturated aqueous sodium bicarbonate solution. The aqueous phase was separated and discarded, and fresh water was added to the organic phase. The pH was adjusted to 5.0 with 6N hydrochloric acid and the organic phase was separated, washed with brine, dried over magnesium sulfate and concentrated in vacuo to give the desired product.

B. 6/ 3- fluoromethylpenicillanic acid

By a procedure similar to that in Example 56B, to a solution of 3.2 g of diethylaminosulfur trifluoride in 80 ml* of methylene chloride, cooled to -78°C and kept under a nitrogen atmosphere, was added 6.98 g of 6/3- hydroxymethylpenicillanic acid phenacyl ester in 25 ml of methylene chloride containing 3.2 ml of pyridine. The resulting reaction mixture was stirred for 45 minutes in the cold and then allowed to warm to room temperature. The reaction solution was washed with water (2 x 100 ml) and a saturated salt solution (2 x 100 ml) and dried over magnesium sulfate. The organic phase was separated and concentrated to dryness in vacuo. The residue was chromatographed on silica gel and the fractions containing the desired material were combined and concentrated to give the intermediate.

C. 6fi-fluoromethylpenicillanic acid

The above-mentioned residual product was dissolved in 25 ml of dry dimethylformamide and was treated with 375 mg of potassium thiophenoxide in 4 ml of dimethylformamide. After stirring at room temperature for 2 hours, the reaction mixture was added to 60 ml of a saturated aqueous sodium bicarbonate solution. Ethyl acetate (60 ml) was added and the organic phase was separated and fresh ethyl acetate was added.

The pH of the aqueous phase was adjusted to 1.5 with 6N hydrochloric acid, and the organic phase was separated, washed with a saturated salt solution and dried over sodium sulfate. Removal of the solvent in vacuo gives the desired product.

Example 70

Å. Starting from suitable 6/3-hydroxymethylpenicillanic acid, -sulfoxide or -sulfone and necessary α-halomethylcarbonyl reagent, and using the method from example 69A, was

. following compounds prepared:

B. Starting from the esters of Examples 69A and 70A and using the indicated procedure, the following intermediates were synthesized: C. Starting from the esters of Example 70B and using the procedure of Example 69C, the following penicillanic acids were prepared: 6 /3-chloromethylpenicillanic acid, 6/3-chloromethylpenicillanic acid sulfone, 6/3-fluoromethylpenicillanic acid sulfoxide, 6/3-fluoromethylpenicillanic acid> 6^-bromomethylpenicillanic acid, 6j8-bromomethylpenicillanic acid sulfoxide, 6^-bromomethylpenicillanic acid sulfone, 6 /3-chloromethylpenicillanic acid sulfoxide and 60-fluoromethylpenicillanic acid sulfone.

Example 71

6/ ?- chlormethylpenicillanic acid - sulph oxide

A.. O-(60-hydroxymethylpenicillanoyl) benzaldehyde-oxime-sulfoxide To a solution of 2.47 g of 6/3-hydroxymethylpenicillanic acid sulfoxide in 200 ml of methylene chloride was added 1.0 g of triethylamine, and the resulting reaction mixture was cooled to 0°C. Ethyl chloroformate (1.1 g) was added dropwise over a period of 15 minutes and the reaction mixture was kept at 0°C.

for 30 minutes. Benzaldehyde oxime (1.2 g) was added in 10 ml of dry acetone and stirring was continued for 2 hours. The reaction mixture was then allowed to warm to room temperature, and stirring was continued for a further 2 hours. The reaction mixture was filtered and the filtrate concentrated to i ' ■ " 1 ■ ' 1 i

dryness. The residue was partitioned between ethyl acetate (100 ml) and water (50 ml). The aqueous layer was separated and the organic layer washed with a saturated aqueous sodium bicarbonate solution and dried over magnesium sulfate. Removal of the solvent in vacuo gave the desired product.

B. Q-( 6/ 3- chloromethylpenicillanoyl) benzaldehyde oxime sulph oxide

A solution of 2.8 g of O-(6/3-hydroxymethylpenicillanoyl)-benzaldehyde oxime sulfoxide and 4.19 g of triphenylphosphine in 10 ml of carbon tetrachloride was stirred at room temperature for 2.5 hours. The reaction mixture was treated with diethyl ether and the solid filtered and chromatographed on 150 g of silica gel. The fractions containing the product were combined and concentrated in vacuo to dryness.

C. 6/ 3- chlormethylpenicillanic acid- sulf oxide

One and eight tenths of a gram of the above-mentioned residue was dissolved in 25 ml of dimethylformamide, to which was then added 660 mg of potassium thiophenoxide in 10 ml of the same solvent. After stirring for 2 hours at room temperature, the reaction mixture was added to a saturated sodium bicarbonate solution. The aqueous liquid was extracted with 75 ml of ethyl acetate, and the organic phase was separated. The pH of the aqueous liquid was adjusted to 1.5 with 6N hydrochloric acid and

extracted with ethyl acetate. The organic phase was separated, dried over sodium sulfate and concentrated in vacuo to dryness,

and this gave the desired product.

Example 72

A. Starting from the appropriate 6/5-hydroxymethylpenicillanic acid,

-sulfoxide or -sulfone, and using the method from example 71A, the following compounds were prepared: 0-(6/3-hydroxymethylpenicillanoyl)benzaldehyde-oxime and 0-(60-hydroxymethylpenicillanoyl)benzaldehyde-oxime-sulfone.

B. Starting from the esters from examples 71A and 72A, and using the indicated method, the following intermediates were prepared: 0-(6/3-fluoromethylpenicillanoyl)benzaldehyde oxime - method from example 65; O-(6/3-fluoromethylpenicillanoyl)benzaldehyde oxime sulfoxide - method from Example 65; O-(6/S-Fluoro-methylpenicillanoyl)benzaldehyde-oxime-sulfone - method from example 65; O-(6/3-Chloromethylpenicillanoyl)benzaldehyde oxime - method from Example 66; O-(6N-chloromethylpenicillanoyl)-benzaldehyde-oxime-sulfoxide - method from example 66; O-(6/3-bromopenicillanoyl)benzaldehyde oxime sulfoxide - method from Example 67; and 0-(6/3-bromomethylpenicillanoyl)-benzaldehyde-oxime-sulfone - method from example 67., C. Starting from the esters from example 72B and applying the method from example 71C, the following compounds were synthesized: 6/ 3-fluoromethylpenicillanic acid, 6/3-fluoromethylpenicillanic acid sulfoxide, 6/3-fluoromethylpenicillanic acid sulfone, 6/3-chloromethylpenicillanic acid, 6/3-chloromethylpenicillanic acid sulfone, 60-bromomethylpenicillanic acid sulfoxide and 6/8-bromomethylpenicillanic acid sulfone.

Example 73

6/ 3-bromomethyl<p>enicill<a>nic acid

A. Benzhydryl-6-hydroxymethylpenicillanate

Diphenyldiazomethane (19.4 g) in 100 ml of ether was added to a solution of 23.1 g of .6/3-hydroxymethylpenicillanic acid in 200 ml of tetrahydrofuran. After 2 hours, the solvents were removed under vacuum and the residue was dissolved in methylene chloride and washed with saturated aqueous sodium bicarbonate solution.

The organic phase was dried over magnesium sulfate and in- steamed. The crude product was triturated with a mixture of ether and petroleum ether (b.p. 40 - 60°C) and filtered, and this gave

the desired intermediate.

B. Benzhydryl-6/3-bromomethylpenicillanate

To a solution of 1.03 g of benzhydryl-6/3-hydroxymethylpenicillanate and 2.2 g of carbon tetrabromide in 5 ml of methylene chloride cooled to 0°C and under a nitrogen atmosphere, 1.47 g of triphenylphosphine in 6 ml of methylene chloride. After 1.5 hours of stirring at 0°C, the reaction solvent was removed in vacuo and the residue was chromatographed on silica gel. The fractions containing the product were combined and concentrated to dryness.

C. 6/ 3-bromomethylpenicillanic acid

Trifluoroacetic acid (0.5 ml) was added to 80 mg of benzhydryl-60-bromomethylpenicillanate in 1 ml of methylene chloride, and the reaction mixture was stirred for 30 minutes at room temperature. The mixture was evaporated to dryness to give the crude product which was purified by chromatography on silica gel.

Example 74

A. Starting from the appropriate 6/3-hydroxymethylpenicillanic acid sulfoxide or sulfone and diphenyldiazomethane, and following the procedure of Example 73A, the following intermediate* compounds were prepared: benzhydryl-6/3-hydroxymethylpenicillanate sulfoxide and benzhydryl- 6/3-Hydroxymethyl penicillanate sulfon.

B. Using the appropriate benzhydryl-6/3-hydroxymethylpenicillanate and applying the stated procedure, the following compounds were prepared:

C. Using the appropriate ester from Example 74B and using the procedure of Example 73C, the following products were synthesized: 6/3-fluoromethylpenicillanic acid, 6/3-fluoromethylpenicillanic acid sulfoxide, 6j3-chloromethylpenicillanic acid sulfoxide, 6/ 3-chloromethylpenicillanic acid sulfone, 6/3-bromomethylpenicillanic acid, 6/3-bromomethylpenicillanic acid sulfoxide and 6/3-bromomethylpenicillanic acid sulfone.

Example 75

6/ 3- fluoromethylpenicillanic acid sulfon

A. 4- methoxybenzyl- 6ft- hydroxyethylpenicillanate- sulfone

To a solution of 2.6 g of 6/3-hydroxymethylpenicillanic acid sulfone and 2.01 g of 4-methoxybenzyl bromide in 50 ml of a 1:1 mixture of dry dimethylformamide-tetrahydrofuran cooled to 0°C, was added dropwise over 20 minutes added 1.4 ml of triethylamine. The solution was stirred in the cold for 4 hours and then treated with . 150 ml of ethyl acetate and 125 ml of a saturated aqueous sodium bicarbonate solution. The aqueous phase was separated and discarded, and fresh water was added to the organic phase. The pH was adjusted to 5.0 with 6N hydrochloric acid and the organic phase was separated, washed with brine, dried over magnesium sulfate and concentrated in vacuo to give the desired product.

B. 4- methoxybenzyl- 6/ 3- fluoromethylpenicillanate- sulfone

To a cold solution (-78°C) of 3.2 g of diethylaminosulfur trifluoride in 85 ml of dry methylene chloride under a nitrogen atmosphere was added 7.0 g of 4-methoxybenzyl-60-hydroxymethylpenicillanate in 25 ral of methylene chloride containing 3.2 ml of pyridine. The resulting reaction mixture was stirred at -78°C for one hour and then allowed to warm to room temperature. The reaction mixture was washed with hot water (2 x 100 mL) and a saturated saline solution (2 x 100 mL) and dried over magnesium sulfate. The organic layer was concentrated to dryness, and this gave the intermediate product.

C. 6/ 3- fluoromethylpenicillanic acid sulfon

4-Methoxybenzyl-6β-fluoromethylpenicillanate sulfone (90 mg) was dissolved in 2 ml of methylene chloride, to which 1 ml of trifluoroacetic acid and 3 drops of anisole were then added. The mixture was stirred at room temperature for 5 hours and then evaporated to dryness. The residue was chromatographed on silica gel. The fractions containing the product were combined and concentrated to give the desired product.

Example 76

A. Using the appropriate 6/3-hydroxymethylpenicillanic acid, -sulfoxide or -sulfone and the necessary halide, and using the procedure of Example 75A, the following intermediates were prepared:

B. Starting from the esters in example 76A, and applying the stated procedure, the following compounds were prepared:

C. Using the esters in Example 76B, and using the method of Example 75C, the following compounds were synthesized in 6£-fluoroethylpenicillanic acid, 6/3-chloromethylpenicillanic acid, 6/8-bromomethylpenicillanic acid, 6/3-fluoromethylpenicillanic acid sulfoxide, 6/3-chloromethylpenicillanic acid sulfoxide, 6/3-bromomethylpenicillanic acid sulfoxide, 6/3-fluoromethylpenicillanic acid sulfone, 60-chloroethylpenicillanic acid sulfone and 60-bromomethylpenicillanic acid sulfone.

Example 77

6/ 3-bromomethylpenicillanic acid

A. • 6/ 3- hydroxymethylpenicillanic acid methyl acetoacetate ester

To 3.22 g of 60-hydroxymethylpenicillanic acid sodium salt i

1.6 ml of methyl-2-chloroacetoacetate was added to 100 ml of dimethylformamide, and the resulting reaction mixture was stirred overnight at room temperature. The mixture was poured into 400 ml of ice and water and extracted with ethyl acetate. The organic phase was separated and washed successively with water, a saturated aqueous sodium bicarbonate solution and a saline solution. The organic phase was then dried over magnesium sulfate and concentrated, and chromatographed on silica gel. The fractions of the eluate containing the product were combined and concentrated in vacuo to give the desired product

product.

B. 6/ 3-Brorametylpenicillanic acid methyl acetoacetate ester

To a solution of 897 mg of 6/3-hydroxymethylpenicillanic acid methyl acetoacetate ester and 2.2 g of carbon tetrabromide in 5 ml of methylene chloride cooled to 0 C and kept under a nitrogen atmosphere, 1.47 g of triphenylphosphine in 7 ml of methylene chloride was added dropwise. . After stirring for 1.5 hours at 0°C, the reaction mixture was allowed to warm to room temperature and was concentrated to dryness. The remaining material was chromatographed on silica gel, and the fractions containing the product were combined and concentrated to give the desired intermediate.

C. 6/ 3- bromopenicillanic acid

To 4.1 g of 6/3-bromomethylpenicillanic acid methyl acetoacetate ester, prepared by the above procedure, in 50 ml of acetone, 2.1 g of sodium nitrite in 10 ml of water was added with stirring. After stirring for 3 hours at room temperature, the solvent was removed in vacuo and the remaining aqueous liquid was extracted once with ether. The aqueous liquid was then acidified to pH 1.5 with 6N hydrochloric acid and was extracted with ethyl acetate. The organic phase was dried over sodium sulfate and concentrated under reduced pressure to give the desired product.

Example 78

A. Starting from the appropriate 6/S-hydroxymethylpenicillanic acid, -sulfoxide or -sulfone and the required 2-chloroacetbacetate, and using the procedure of Example 77A, the following compounds were prepared:

B. By using the esters from example 77A and using the specified method, the following intermediates were synthesized: C. By starting from the esters in example 78B, and using the method in example 77C, the following compounds were prepared: 6/ 3-fluoromethylpenicillanic acid, 60-chloromethylpenicillanic acid, 6/3-bromomethylpenicillanic acid, 6/3-bromomethylpenicillanic acid, 6/3-f fluoromethylpenicillanic acid-sulfoxide, 6/5-chloromethylpenicillanic-r acid-sulfoxide, 6/3-bromomethylpenicillanic acid-sulfoxide , 6/3-fluoromethylpenicillanic acid sulfone, 60-chloromethylpenicillanic acid sulfone and 60-bromomethylpenicillanic acid sulfone.'•

Example 79

6ft- chloromethylpenicillanic acid

A. 6/ 3- hydroxymethylpenicillanic acid dimethoxyphosphine ester

To a solution of 2.31 g of 6/3-hydroxymethylpenicillanic acid in 40 ml of methylene chloride was added 1.08 g of triethylamine, and the solution was treated with 1.28 g of dimethoxychlorophosphine and stirred for 30 minutes. The solvent was removed in vacuo and the residue treated with 125 ml of dry diethyl ether. The insoluble triethylamine hydride was filtered and the ether removed under reduced pressure to provide the desired intermediate.

B. 6/ Mchlormethylpenicillanic acid diraethoxyphosphine ester

To 5 ml of carbon tetrachloride containing 1.29 g of 6/3-hydroxymethylpenicillanic acid dimethoxyphosphine ester, 1.88 g of triphenylphosphine was added, and the resulting solution was stirred at room temperature for 3 hours. The reaction mixture was treated with diethyl ether (75 mL), and the resulting slurry was filtered and chromatographed on silica gel. The fractions containing the desired material were combined and concentrated in vacuo to give the intermediate.

C. 6ft- chlorpenicillanic acid

The remaining material above was dissolved in 10 ml. ethyl acetate-water<p>g pH was adjusted to 5. After stirring at room temperature for 20 minutes, the organic layer was separated, dried over magnesium sulfate and concentrated to dryness to give the desired product.

Example 80

A. Starting from the appropriate 6/?-hydroxypenicillanic acid, -sulfoxide or -sulfone, and using the procedure of Example 79A, the following compounds were prepared:

B. By using the esters from Example 80A and using the stated methods, the following intermediates were synthesized: .. _

C. Using the above-mentioned esters from example 80B, and using the method in example 79C, the following compounds were synthesized: 6/3-chloromethylpenicillanic acid, 6/3-chloromethylpenicillanic acid sulfoxide, 6Æ-chloromethylpenicillanic acid sulfone, 60-bromomethylpenicillanic acid, 6/3-bromomethylpenicillanic acid sulfoxide and 6/3-bromomethylpenicillanic acid sulfone.

Example 81

6/ 3- f fluoromethylpenicillanic acid

To a solution of 40 ml of dry methylene chloride containing 1.6 g of diethylaminosulfur trifluoride at -78°C and under a nitrogen atmosphere was added 3.23 g of 6/3-hydroxymethylpenicillanic acid dimethoxyphosphine ester (Example 79A) and 1.6 ml of pyridine in 10 ml of methylene chloride. The reaction mixture was stirred at -78°C for 45 minutes and then allowed to warm to room temperature. The reaction mixture was then treated with 100 ml of water, and the pH was adjusted to 5.0 with 6N hydrochloric acid. The organic phase was separated, dried over magnesium sulfate and concentrated under reduced pressure to dryness. The final product was purified by chromatography on silica gel.

Example 82

6/ 3- chloromethylpenicillanic acid

A. 3. 5- di- t-butyl- 4- hydroxybenzyl- 6/ 3- hydroxymethylpenicillanate

To a solution of 2.3 g of 6j8-hydroxymethylpenicillanic acid in 200 ml of dry methylene chloride was added 1.0 g of triethylamine, and the resulting solution was cooled to 0-5°C. Ethyl chloroformate (1.1 g) was added portionwise to the reaction mixture over a period of 15 minutes. The reaction mixture was maintained

0°C for 30 minutes, and was then treated with 2.36 g of 3,5-di-t-butylbenzyl alcohol. After stirring in the cold for 2 hours, the reaction mixture was allowed to warm to room temperature. Water (75 mL) was added to the reaction mixture and the organic phase was separated, dried over sodium sulfate and concentrated in vacuo to give the desired compound.

B. 3, 5- t-butyl- 4- hydroxybenzyl- 6/ ?- chloroethylpenicillanate

A solution of 1.7 g of 3,5-di-t-butyl-4-hydroxybenzyl-6β-hydroxymethylpenicillanate and 1.88 g of triphenylphosphine in 5 g of carbon tetrachloride was stirred at room temperature for 2 hours. The reaction mixture was treated with diethyl ether and the resulting slurry was filtered.

C. 6/ 3- chloromethylpenicillanic acid

The remaining solid was dissolved in tetrahydrofuran - water (1:1) and the pH was carefully adjusted to 8.0. After stirring for 20 minutes, 100 ml of ethyl acetate was added and the pH was adjusted to 7.0. The ethyl acetate was separated, and fresh ethyl acetate was added to the aqueous liquid and the pH was adjusted to 1.5 with 6N hydrochloric acid. The organic phase was separated, dried over magnesium sulfate and concentrated to give the desired product.

Example 83

A Starting from the required 6/3-hydroxymethylpenicillanic acid sulfoxide and sulfone, and applying the procedure from Example 82A, 3,5-di-t-butyl-4-hydroxybenzyl-6j8-hydroxymethylpenicillanate sulfoxide and 3<, >5<->di-t-but<y>l-4-hydroxy<y>benz<y>l-6/3-hydroxymethylpenicillanate sulfone prepared.

B. Using the appropriate esters from Examples 82A and 83A and using the stated procedure, the following intermediates were synthesized:

C. Starting from the esters of Example 83B, and using the procedure of Example 82C, the following final products were prepared: 6)3-fluoromethylpenicillanic acid, 6/3-bromomethylpenicillanic acid, 6/3-fluoromethylpenicillanic acid sulfoxide, 6 ^-chloromethylpenicillanic acid sulfoxide, 60-bromomethylpenicillanic acid sulfoxide, 6/3-fluoromethylpenicillanic acid sulfone, 6/3-chloromethylpenicillanic acid sulfone and 6/3-bromomethylpenicillanic acid e-sulfone.

Claims (10)

1. Process for preparing a compound selected from those that have the formula where R^c- is selected from the group consisting of fluorine, chlorine, bromine, iodine, alkyl having from one to four carbon atoms and alkylthio having from one to four carbon atoms, n is an integer from 0 to 2, and R^2 is selected from the group consisting of hydrogen and ester-forming residues which are readily hydrolyzable in vivo, characterized by reacting a compound of the formula where X is selected from the group consisting of chlorine, bromine and iodine, and R^ g is selected from the group consisting of ester-forming residues which are readily hydrolyzable in vivo and conventional penicillin carboxy-protecting groups, with an organotin monohydride at ca . 0-110°C, followed by annealing. of R-^g when it is a conventional penicillin-carboxy protecting group, with the proviso that when said R^g is a conventional penicillin-carboxy-protecting group, n is an integer from 0 to 1. 2. Method according to claim 1, characterized in that an organotin monohydride with the formula is used <HSnR>16<R>1<7R> 18 where Ri7 °9 Ris ^ver is selected from the group consisting of alkyl with from one to five carbon atoms, phenyl and benzyl. 3. Method according to claim 2, characterized in that R^ g is a conventional penicillin-carboxy-protecting group selected from the group consisting of a) -PR2 R3 where R2 and R3 are each selected from the group consisting of alkyl with from one to three carbon atoms, alkoxy with from one to three carbon atoms, and phenyl, b) 3,5-di-t-butyl-4-hydroxybenzyl, c) -CH2~ Y where Y is selected from the group consisting of -C(0)R^ where R^ is phenyl or alkyl with from one to three carbon atoms, cyano and carbo alkoxy with from two to four carbon atoms, d) -N=CH-Rg where R^ is selected from the group consisting of phenyl and alkyl with from one to three carbon atoms, e) -CH(COCH3 )CO2 R6 where Rfi is alkyl with from one to four carbon atoms, f) -C <R>^ RgRg where each of R_ and Rg is selected from the group consisting of hydrogen, phenyl and methyl, and Rg is selected from the group consisting of phenyl-4-methoxyphenyl and methyl, with the condition that when each of R^ and Rg are methyl, then Rg is methyl, g) -Si(C <H>3 )3 and -Si(CH3 >2 t-c4 H9°9 h)"" SnR^ gR^ R^ g where R^g» R^ '-..and <R>^ g are each selected from the group consisting of alkyl having from one to five carbon atoms, phenyl and benzyl 4- Method according to claim 3, characterized in that R^ g is a conventional penicillin-carboxy-protecting group ~ SnRi5 <R> i <7> Ri8 ^vor Ri6' R^_ and R^ g are each n- butyl, R^ ,. is chlorine, X is iodine, n is 0 and the organotin monohydride is tri-n-butyltin hydride. 5. Procedure according to kra <y> 3, characterized in that R^ g is a conventional penicillin carboxy protecting group -Si(CH 3 ) 3 , R^ and X are each bromine, n is 0 and the organotin monohydride is tri-n-butyltin hydride. 6. Process according to claim 3, characterized in that R^ g is a conventional penicillin carboxy-protecting group -CR^ RgRg where R7 and Rg are each hydrogen and Rg is 4-methoxyphenyl, R15 and X are each iodine, n is 0 and the organotin monohydride is tri-n-butyltin hydride. v' 7. Method according to claim 3, characterized in that R 1 g is a conventional penicillin carboxy-protecting group -Si(CH 3 ) 3 , R 15 is chlorine and X is iodine, n is 0 and the organotin monohydride is tri-n -butyltin hydride. 8. Method according to claim 2, characterized in that R^ g is an ester-forming residue which is easily hydrolyzable in vivo selected from the group consisting of alkanoyloxymethyl with from 3 to 6 carbon atoms, 1-(alkanoyloxy)ethyl with from 4 to 7 carbon atoms, 1-methyl-1-(alkanoyloxy)ethyl with from 5 to 8 carbon atoms, alkoxycarbonyloxymethyl with from 3 to 6 carbon atoms, 1-(Alkoxycarbonyloxy)ethyl with from 4 to 7 carbon atoms, 1-methyl-l-( alkoxy-carbonyloxy) ethyl having from 5 to 8 carbon atoms, 3-phthalidyl, 4-crotonolactonyl and gamma-butyrolacton-4-yl. 9. Method according to claim 8, characterized in that R^ g is pivaloyloxymethyl, R^ g is chlorine, X is bromine, n is 0 and the organotin monohydride is ' tri-n-butyltin hydride. 10. Method according to claim 8, characterized in that Ri g is pivaloyloxymethyl, R 5 and X are each iodine, n is 0 and the organotin monohydride is tri-n-butyltin hydride. Summary 6-j8-substituted penicillanic acids and derivatives thereof as useful agents for increasing the effectiveness of several /3-lactam antibiotics against many /3-lactamase-producing bacteria, and 6-/3-substituted penicillanic acid derivatives in which the carboxy group is protected with a conventional penicillin carboxy-protecting group as useful intermediates leading to said synergistic funds. A method for converting 6,6-disubstituted penicillanic acid derivatives to the corresponding 6-/3-substituted penicillanic acid congeners.